Merge remote-tracking branch 'origin/main' into fix/pane-cwd-from-process-table

# Conflicts:
#	CHANGELOG.md

CHANGELOG.md

@@ -7,6 +7,18 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- **The window's leading corner carries the app's mark off macOS** — macOS fills
+  the top-left with the traffic lights; on Windows and Linux that corner was
+  empty, with everything the caption row holds (the rail's "+" and collapse, the
+  corner chrome, the window controls) pushed to a right edge. The "duo" mark now
+  heads the tab rail on its content inset, the line the search box and every row
+  label below it start on, and follows the rail's controls into the title strip
+  when the sidebar is collapsed — so the corner never falls back to nothing.
+  Drawn, never clicked: it takes no hover capsule and no hit box, leaving the
+  strip grabbable through it.
+
 ### Fixed
 
 - **New tabs and splits open in the right directory even when the shell can't be
@@ -25,6 +37,27 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   through, and that is the one a new tab should open in. macOS and Linux;
   Windows has no equivalent process query and is unchanged.
 
+- **The editor and diff overlays keep their header on the caption line when the
+  detail panel is open** — off macOS the title bar is hoisted above
+  `[terminal | panel]` so the ─ ▢ ✕ group can reach the window's corner, which
+  left both overlays — anchored to the terminal column — starting 40px down.
+  Their headers are drawn to *be* the title bar while they're up (its height,
+  its insets, a full chrome tile for their one control), and instead landed a
+  row low, level with the panel's tab row. They now hang on the row that owns
+  the bar, inset by the panel's width, so the corner chrome keeps its surface
+  and its clicks.
+- **Those headers became real title bars** — dragging one now moves the window
+  and double-clicking zooms it. Both covered the caption row and neither did
+  either, with the panel open or closed, so opening a file turned the top of the
+  window into a 40px strip that looked exactly like a title bar and answered
+  nothing. Their controls (the ✕, the diff's back-to-all-files chip) are
+  `occlude()`d to keep taking clicks: a drag region on Windows is HTCAPTION, and
+  the OS claims the press before the app hit-tests.
+- **The rail's top zone lines up with the title bar to the pixel** — the bar
+  reserves a hairline inside its own height that the rail's stand-in row didn't,
+  so everything in that row sat half a pixel low. Invisible on the line-art
+  tiles; not on the mark, which visibly hopped as collapsing the rail handed it
+  over to the bar.
 - **CJK and emoji stop falling through to the OS on Windows and Linux** — the
   default `font_fallbacks` named only faces that ship with macOS (Menlo, Apple
   Color Emoji), so off macOS the entire chain matched nothing and every

src/core/crash.rs

@@ -0,0 +1,141 @@
+//! Crash log — the panic message the OS crash reporter throws away.
+//!
+//! Most tty7 panics happen inside a gpui input callback, and those callbacks are
+//! `extern "C"`: the panic can't unwind across them, so the runtime aborts. What
+//! macOS then records is the *abort* — `panic_cannot_unwind` on top of
+//! `handle_key_event` — with no message, no `file:line`, and the original frames
+//! already unwound away. Reports like that are undiagnosable, and the GUI has no
+//! logger and no terminal to print to.
+//!
+//! So we write the two lines that matter (message + location, plus a backtrace)
+//! to `crash.log` in the config dir before the process goes down.
+
+use std::fmt::Write as _;
+use std::path::PathBuf;
+
+/// Rewrite the log once it passes this, so a panic loop can't grow it forever.
+const MAX_BYTES: u64 = 256 * 1024;
+
+/// Install the panic hook for this process. `role` labels the records, since the
+/// GUI and the daemon it spawns share one config dir. Chains to the previously
+/// installed hook, so the usual stderr output still happens when there's a
+/// terminal to see it.
+pub fn install(role: &'static str) {
+    let previous = std::panic::take_hook();
+    std::panic::set_hook(Box::new(move |info| {
+        record(role, info);
+        previous(info);
+    }));
+}
+
+/// Append one record. Every step is best-effort: a panic handler that panics
+/// (or fails loudly) is worse than one that loses a log line.
+fn record(role: &str, info: &std::panic::PanicHookInfo<'_>) {
+    let Some(path) = log_path() else {
+        return;
+    };
+    let thread = std::thread::current();
+    let mut record = String::new();
+    // `info` renders as "panicked at <file:line:col>:\n<message>" — the exact
+    // pair the crash report is missing.
+    let _ = write!(
+        record,
+        "\n=== {} {} v{} pid {} thread {:?}\n{info}\n{}\n",
+        utc_timestamp(),
+        role,
+        env!("CARGO_PKG_VERSION"),
+        std::process::id(),
+        thread.name().unwrap_or("<unnamed>"),
+        std::backtrace::Backtrace::force_capture(),
+    );
+    append(&path, &record);
+}
+
+fn append(path: &PathBuf, record: &str) {
+    use std::io::Write as _;
+    let truncate = std::fs::metadata(path).is_ok_and(|m| m.len() > MAX_BYTES);
+    let mut file = match std::fs::OpenOptions::new()
+        .create(true)
+        .append(!truncate)
+        .write(true)
+        .truncate(truncate)
+        .open(path)
+    {
+        Ok(f) => f,
+        Err(_) => return,
+    };
+    let _ = file.write_all(record.as_bytes());
+    let _ = file.flush();
+}
+
+fn log_path() -> Option<PathBuf> {
+    crate::core::config::config_path("crash.log")
+}
+
+/// `YYYY-MM-DD HH:MM:SS UTC` from the epoch seconds, so a record can be lined up
+/// against an OS crash report without pulling in a date crate.
+fn utc_timestamp() -> String {
+    let secs = std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .map(|d| d.as_secs())
+        .unwrap_or(0);
+    let (days, rem) = (secs / 86_400, secs % 86_400);
+    let (y, m, d) = civil_from_days(days as i64);
+    format!(
+        "{y:04}-{m:02}-{d:02} {:02}:{:02}:{:02} UTC",
+        rem / 3600,
+        (rem % 3600) / 60,
+        rem % 60
+    )
+}
+
+/// Howard Hinnant's `civil_from_days`: days since the Unix epoch → (y, m, d).
+fn civil_from_days(z: i64) -> (i64, u32, u32) {
+    let z = z + 719_468;
+    let era = z.div_euclid(146_097);
+    let doe = z.rem_euclid(146_097);
+    let yoe = (doe - doe / 1460 + doe / 36_524 - doe / 146_096) / 365;
+    let y = yoe + era * 400;
+    let doy = doe - (365 * yoe + yoe / 4 - yoe / 100);
+    let mp = (5 * doy + 2) / 153;
+    let d = (doy - (153 * mp + 2) / 5 + 1) as u32;
+    let m = if mp < 10 { mp + 3 } else { mp - 9 } as u32;
+    (if m <= 2 { y + 1 } else { y }, m, d)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{civil_from_days, install, log_path};
+
+    /// The whole point of the hook: after a panic, the message and its location
+    /// are on disk. `catch_unwind` stands in for the abort — the hook runs
+    /// before either outcome.
+    #[test]
+    fn a_panic_lands_in_the_crash_log() {
+        // Same pinned temp dir the config tests use (set-once, first call wins).
+        let dir = std::env::temp_dir().join(format!("tty7-covtest-{}", std::process::id()));
+        std::fs::create_dir_all(&dir).ok();
+        crate::core::config::set_config_dir(dir);
+        let path = log_path().expect("a pinned config dir resolves a log path");
+        let _ = std::fs::remove_file(&path);
+
+        install("test");
+        let _ = std::panic::catch_unwind(|| panic!("crash-log probe"));
+
+        let body = std::fs::read_to_string(&path).expect("the hook wrote a record");
+        assert!(body.contains("crash-log probe"), "message: {body}");
+        // Bare file name: `panic!`'s location carries the platform's own
+        // separator (`src\core\crash.rs` on Windows).
+        assert!(body.contains("crash.rs:"), "location: {body}");
+        assert!(body.contains("test v"), "role + version: {body}");
+    }
+
+    #[test]
+    fn civil_from_days_matches_known_dates() {
+        assert_eq!(civil_from_days(0), (1970, 1, 1));
+        assert_eq!(civil_from_days(20_660), (2026, 7, 26));
+        // Leap day, and the day after it.
+        assert_eq!(civil_from_days(19_782), (2024, 2, 29));
+        assert_eq!(civil_from_days(19_783), (2024, 3, 1));
+    }
+}

src/core/mod.rs

@@ -12,6 +12,7 @@ pub mod agent_hooks;
 pub mod agent_prompt;
 pub mod cli_agent;
 pub mod config;
+pub mod crash;
 // SSH connection-manager data layer (WS1). Its public API is consumed by the
 // daemon-session, auth, forwarding, and UI workstreams, which land separately —
 // so parts of it read as dead code until those merge.

src/main.rs

@@ -298,6 +298,17 @@ fn main() {
     // under this dir too, so the order matters).
     apply_config_dir_arg();
 
+    // Panics inside gpui's `extern "C"` input callbacks abort instead of
+    // unwinding, and the OS crash report then holds the abort rather than the
+    // panic — no message, no location. Record those to `crash.log` in the config
+    // dir. Installed here, right after the config dir resolves, so both the GUI
+    // and the daemon below are covered from their first line of real work.
+    crate::core::crash::install(if std::env::args().any(|a| a == "--daemon") {
+        "daemon"
+    } else {
+        "gui"
+    });
+
     // Daemon mode: when launched with `--daemon` we run the headless persistent
     // terminal server and never open a window. This is the backing process the GUI
     // auto-spawns and reconnects to; it owns all PTYs + child shells and outlives

src/terminal/remote.rs

@@ -236,6 +236,24 @@ impl RemoteTerminal {
         let retry_shell = shell.clone();
         match Self::spawn_once(size, cell_w, cell_h, cwd, shell) {
             Ok(term) => Ok(term),
+            Err(first_err) if daemon_not_listening(&first_err) => {
+                // Nothing is on the socket: the daemon died (crash, OOM, a stray
+                // `kill`) since the last pane was opened. Every later spawn would
+                // fail the same way, so bring one back up and retry rather than
+                // leaving the window unable to open another terminal.
+                if let Err(start_err) = crate::daemon::spawn::ensure_running() {
+                    return Err(anyhow::anyhow!(
+                        "daemon not running ({first_err}); starting one failed: {start_err}"
+                    ));
+                }
+                Self::spawn_once(size, cell_w, cell_h, retry_cwd, retry_shell).map_err(
+                    |second_err| {
+                        anyhow::anyhow!(
+                            "daemon not running ({first_err}); started one but Spawn still failed: {second_err}"
+                        )
+                    },
+                )
+            }
             Err(first_err) if daemon_disconnected_before_spawn_reply(&first_err) => {
                 // A live-but-old daemon can accept the connection, panic while
                 // handling Spawn, and close before replying. Restart once so an
@@ -1430,6 +1448,21 @@ fn record_mark(term: &Term<EventProxy>, marks: &crate::terminal::marks::Marks, e
     }
 }
 
+/// Whether the failure is "nothing is listening on the socket" — the daemon is
+/// gone, as opposed to alive but unhappy. On Unix a dead daemon leaves the
+/// socket file behind (`ConnectionRefused`) or removed it on the way out
+/// (`NotFound`); on Windows the named pipe simply isn't there (`NotFound`).
+fn daemon_not_listening(err: &anyhow::Error) -> bool {
+    err.chain().any(|cause| {
+        cause.downcast_ref::<std::io::Error>().is_some_and(|io| {
+            matches!(
+                io.kind(),
+                std::io::ErrorKind::ConnectionRefused | std::io::ErrorKind::NotFound
+            )
+        })
+    })
+}
+
 fn daemon_disconnected_before_spawn_reply(err: &anyhow::Error) -> bool {
     err.chain().any(|cause| {
         cause.downcast_ref::<std::io::Error>().is_some_and(|io| {
@@ -1604,10 +1637,14 @@ fn parse_osc_notification(payload: &[u8]) -> Option<(Option<String>, String)> {
 /// isolation (dev vs. real config dir), exactly like every other config-dir file.
 fn connect() -> anyhow::Result<Stream> {
     transport::connect().map_err(|e| {
-        anyhow::anyhow!(
-            "connect to daemon at {}: {e}",
+        // `context`, not a formatted `anyhow!`: callers classify the failure by
+        // downcasting to `io::Error` (see `daemon_not_listening`), and
+        // interpolating the cause into a string would leave the chain with
+        // nothing to find.
+        anyhow::Error::new(e).context(format!(
+            "connect to daemon at {}",
             transport::endpoint_display()
-        )
+        ))
     })
 }
 
@@ -1742,6 +1779,31 @@ mod tests {
         assert!(!daemon_disconnected_before_spawn_reply(&refused));
     }
 
+    /// A dead daemon is the one failure the client can fix by itself, and it
+    /// must be told apart from a live daemon saying no — restarting on *that*
+    /// would kill every running pane over a bad shell setting.
+    #[test]
+    fn only_a_dead_daemon_is_worth_starting_one_for() {
+        let connect_failed = |kind| -> anyhow::Error {
+            anyhow::Error::new(std::io::Error::new(kind, "no listener"))
+                .context("connect to daemon at /tmp/tty7.sock")
+        };
+        assert!(daemon_not_listening(&connect_failed(
+            std::io::ErrorKind::ConnectionRefused
+        )));
+        assert!(daemon_not_listening(&connect_failed(
+            std::io::ErrorKind::NotFound
+        )));
+
+        // A daemon that answered and refused, and one that hung up mid-Spawn:
+        // neither is "not running", and each has its own recovery.
+        let refused = anyhow::anyhow!("daemon refused Spawn: configured shell missing");
+        assert!(!daemon_not_listening(&refused));
+        let eof: anyhow::Error =
+            std::io::Error::new(std::io::ErrorKind::UnexpectedEof, "closed").into();
+        assert!(!daemon_not_listening(&eof));
+    }
+
     /// Without a real daemon, drive the reader path directly: a `UnixStream::pair`
     /// stands in for the connection. We hand `RemoteTerminal` one half (as if it
     /// were the attach'd socket) and push framed `DaemonMsg`s down the other, then

src/terminal/smart_select.rs

@@ -71,6 +71,16 @@ pub(super) fn grid_smart_range<T: EventListener>(
     term: &Term<T>,
     click: Point,
 ) -> Option<SmartRange> {
+    // 0) The click carries the geometry of the frame that dispatched it, and
+    //    the grid can shrink out from under it (a split, a window drag, a
+    //    replayed attach size landing on the reader thread). Both walks below
+    //    index `grid[click.line]` straight away, and `Grid`'s `Index<Line>`
+    //    only `debug_assert`s the bound — a release build walks off the
+    //    storage. Same guard, same reason, as `TerminalView::grid_line`.
+    if click.line < term.topmost_line() || click.line > term.bottommost_line() {
+        return None;
+    }
+
     // 1) An explicit OSC 8 hyperlink run wins outright — the program told us
     //    the exact extent, no guessing needed.
     if let Some((start, end)) = hyperlink_run(term, click) {
@@ -805,6 +815,20 @@ mod tests {
         assert!(grid_smart_range(&term, Point::new(Line(0), Column(99))).is_none());
     }
 
+    /// A double-click dispatched with the previous frame's geometry can name a
+    /// row the grid has since dropped. Indexing it walks off the storage, and
+    /// the click arrives in a gpui `extern "C"` callback where that panic
+    /// aborts instead of unwinding — so the row has to be refused first.
+    #[test]
+    fn click_outside_the_grid_rows_yields_no_range() {
+        let term = term_with(10, 2, "hello");
+        // Below the last row of a shrunken grid...
+        assert!(grid_smart_range(&term, Point::new(Line(2), Column(0))).is_none());
+        assert!(grid_smart_range(&term, Point::new(Line(9_000), Column(0))).is_none());
+        // ...and above the top of a scrollback this short.
+        assert!(grid_smart_range(&term, Point::new(Line(-1), Column(0))).is_none());
+    }
+
     fn selected(text: &str, click: usize) -> Option<String> {
         let chars: Vec<char> = text.chars().collect();
         range(text, click).map(|(s, e)| chars[s..=e].iter().collect())

src/terminal/view.rs

@@ -93,6 +93,18 @@ pub struct NativeSshParts {
     persist: Box<crate::daemon::protocol::NativeSshSpec>,
 }
 
+/// An established shell daemon pane (fresh spawn or re-attach), ready to be
+/// wrapped in a view: the output of the fallible
+/// [`TerminalView::spawn_shell_terminal`], consumed by the infallible
+/// [`TerminalView::from_shell_parts`].
+pub struct ShellParts {
+    terminal: RemoteTerminal,
+    pane_id: u64,
+    /// The explicit shell pick this pane was spawned with, if any; `None` for a
+    /// re-attached pane (the pick isn't persisted).
+    shell_spec: Option<ShellSpec>,
+}
+
 /// See `TerminalView::drag_scroll`.
 #[derive(Clone, Copy)]
 struct DragScroll {
@@ -816,19 +828,25 @@ fn fallback_chain(family: &str, configured: &[String]) -> Vec<String> {
 }
 
 impl TerminalView {
-    pub fn new(
+    /// The fallible half of a shell-backed view: establish the daemon pane
+    /// *before* the view is built, so a refused spawn (daemon down, spawn
+    /// error) comes back as an `Err` the caller can report. Splitting it out
+    /// matters beyond tidiness: the view is constructed inside `cx.new`, deep
+    /// under gpui's `extern "C"` input callbacks, where a panic can't unwind
+    /// and aborts the process instead. Mirrors
+    /// [`Self::spawn_native_ssh_terminal`].
+    ///
+    /// Provisional size; corrected on the first prepaint once we can measure.
+    /// The PTY lives in the daemon now. On session restore (`restore_pane`),
+    /// re-`attach` to the still-running pane so its process + scrollback come
+    /// back intact; otherwise `spawn` a fresh pane (with the caller's shell
+    /// pick, if any). The caller only passes a `restore_pane` it has already
+    /// confirmed alive, so we trust it here.
+    pub fn spawn_shell_terminal(
         working_directory: Option<std::path::PathBuf>,
         restore_pane: Option<u64>,
         shell: Option<ShellSpec>,
-        window: &mut Window,
-        cx: &mut Context<Self>,
-    ) -> anyhow::Result<Self> {
-        // Provisional size; corrected on the first prepaint once we can measure.
-        // The PTY lives in the daemon now. On session restore (`restore_pane`),
-        // re-`attach` to the still-running pane so its process + scrollback come
-        // back intact; otherwise `spawn` a fresh pane (with the caller's shell
-        // pick, if any). The caller only passes a `restore_pane` it has already
-        // confirmed alive, so we trust it here.
+    ) -> anyhow::Result<ShellParts> {
         let (terminal, pane_id, shell_spec) = match restore_pane {
             Some(id) => (
                 RemoteTerminal::attach(TermSize::new(80, 24), 8, 17, id)?,
@@ -848,9 +866,23 @@ impl TerminalView {
                 (terminal, id, shell)
             }
         };
-        let mut view = Self::with_terminal(terminal, pane_id, window, cx);
-        view.shell_spec = shell_spec;
-        Ok(view)
+        Ok(ShellParts {
+            terminal,
+            pane_id,
+            shell_spec,
+        })
+    }
+
+    /// Wrap an established shell pane (from [`Self::spawn_shell_terminal`]) in
+    /// a view. Infallible by construction — see that function.
+    pub fn from_shell_parts(
+        parts: ShellParts,
+        window: &mut Window,
+        cx: &mut Context<Self>,
+    ) -> Self {
+        let mut view = Self::with_terminal(parts.terminal, parts.pane_id, window, cx);
+        view.shell_spec = parts.shell_spec;
+        view
     }
 
     /// Spawn a native (russh) SSH pane for `spec` and build the view around it
@@ -1160,6 +1192,18 @@ impl TerminalView {
         cell_width: Pixels,
         line_height: Pixels,
     ) {
+        // A remembered hover cell describes the *old* geometry: after a resize
+        // its row may not exist any more, and the pointer sits over a different
+        // cell regardless. Forget it — the next mouse move records a fresh one.
+        // (`grid_line` also refuses a stale row, so this is about not underlining
+        // the wrong cell, not about safety.) The link that cell resolved to goes
+        // with it: it is held in grid coordinates the reflow just moved text
+        // under, so keeping it would underline whatever now sits there (and hold
+        // the pointing-hand cursor over it) until the pointer moves again.
+        if (cols, rows) != (self.terminal.size().cols, self.terminal.size().rows) {
+            self.last_hover_cell = None;
+            self.hovered_link = None;
+        }
         self.cell_width = cell_width;
         self.line_height = line_height;
         self.terminal.resize(
@@ -4335,6 +4379,23 @@ impl TerminalView {
         }
     }
 
+    /// The grid line a screen `row` currently maps to, or `None` when that row
+    /// is outside the grid.
+    ///
+    /// Mandatory before indexing: `Grid`'s `Index<Line>` only `debug_assert`s
+    /// the bound, so a release build walks off the storage and panics on the
+    /// slice check instead. A remembered cell goes stale whenever the grid
+    /// shrinks under it — split a pane, drag the window smaller — and the
+    /// callers here run inside gpui's `extern "C"` input callbacks, where that
+    /// panic can't unwind and aborts the process.
+    fn grid_line(
+        term: &alacritty_terminal::Term<crate::terminal::remote::EventProxy>,
+        row: usize,
+    ) -> Option<Line> {
+        let line = Line(row as i32 - term.grid().display_offset() as i32);
+        (line >= term.topmost_line() && line <= term.bottommost_line()).then_some(line)
+    }
+
     /// Open the link under the given cell, if any (OSC 8 hyperlink, plain URL or
     /// existing file or directory path detected in the row text). Returns true if one opened.
     pub fn open_link_at(&self, col: usize, row: usize, cx: &mut Context<Self>) -> bool {
@@ -4342,8 +4403,9 @@ impl TerminalView {
             return false;
         }
         let term = self.terminal.term.lock();
-        let display_offset = term.grid().display_offset() as i32;
-        let line = Line(row as i32 - display_offset);
+        let Some(line) = Self::grid_line(&term, row) else {
+            return false;
+        };
         let cols = term.columns();
         if col >= cols {
             return false;
@@ -4490,8 +4552,7 @@ impl TerminalView {
         include_loopback: bool,
     ) -> Option<HoveredLink> {
         let term = self.terminal.term.lock();
-        let display_offset = term.grid().display_offset() as i32;
-        let line = Line(row as i32 - display_offset);
+        let line = Self::grid_line(&term, row)?;
         let cols = term.columns();
         if col >= cols {
             return None;
@@ -6790,6 +6851,60 @@ mod gpui_tests {
         (window, daemon_side)
     }
 
+    /// A hover cell remembered while the pane was tall names a row the grid no
+    /// longer has once the pane shrinks (a vertical split, a smaller window).
+    /// Resolving it must decline rather than index the grid — this path runs
+    /// from `ModifiersChanged` (the ⌘ of the very ⌘⇧D that split the pane), an
+    /// `extern "C"` callback where the panic can't unwind and aborts the app.
+    #[gpui::test]
+    fn a_stale_hover_row_does_not_index_the_shrunken_grid(cx: &mut TestAppContext) {
+        let (window, _daemon) = harness(cx);
+        window
+            .update(cx, |view, _, cx| {
+                // Hover the last row of the 24-row grid, then shrink to 8 rows.
+                view.hover_link_at(0, 23, true, cx);
+                view.terminal.resize(TermSize::new(80, 8), 8, 17);
+                // `set_grid_size` drops the stale cell in the real app; pin it
+                // here so the guard inside the lookup is what's under test.
+                view.last_hover_cell = Some((0, 23));
+                assert!(
+                    !view.refresh_link_hover(true, cx),
+                    "a row outside the grid can't hold a link"
+                );
+            })
+            .unwrap();
+    }
+
+    /// The other half of the fix: the pane that shrank forgets the hover it was
+    /// holding, rather than carrying a cell (and the underline it resolved) that
+    /// now names different text.
+    #[gpui::test]
+    fn a_resize_forgets_the_hovered_cell(cx: &mut TestAppContext) {
+        let (window, _daemon) = harness(cx);
+        window
+            .update(cx, |view, _, cx| {
+                // Pin a known geometry first — what the test window measured for
+                // itself is the element's business, and this is about the
+                // transition. Then hover the last row of those 24.
+                view.set_grid_size(80, 24, px(8.), px(17.));
+                view.hover_link_at(0, 23, true, cx);
+                assert_eq!(view.last_hover_cell, Some((0, 23)));
+                view.hovered_link = Some(HoveredLink {
+                    line: 23,
+                    start: 0,
+                    end: 3,
+                });
+                // The same geometry again changes nothing...
+                view.set_grid_size(80, 24, px(8.), px(17.));
+                assert_eq!(view.last_hover_cell, Some((0, 23)));
+                // ...but a split (or a window drag) that shrinks the pane does.
+                view.set_grid_size(80, 8, px(8.), px(17.));
+                assert!(view.last_hover_cell.is_none(), "the cell is stale");
+                assert!(view.hovered_link.is_none(), "so is the link it resolved");
+            })
+            .unwrap();
+    }
+
     #[gpui::test]
     fn title_events_drive_the_tab_title(cx: &mut TestAppContext) {
         let (window, _daemon) = harness(cx);

src/ui/app.rs

@@ -9,7 +9,9 @@ use gpui_component::color_picker::{ColorPickerEvent, ColorPickerState};
 use gpui_component::input::{InputEvent, InputState};
 use gpui_component::select::{SearchableVec, SelectEvent, SelectState};
 use gpui_component::slider::{SliderEvent, SliderState};
-use gpui_component::{ActiveTheme as _, IndexPath, TitleBar, WindowExt as _};
+use gpui_component::{
+    ActiveTheme as _, IndexPath, InteractiveElementExt as _, TitleBar, WindowExt as _,
+};
 use std::cell::{Cell, RefCell};
 use std::collections::HashSet;
 use std::rc::Rc;
@@ -190,6 +192,93 @@ pub(crate) fn title_bar_hug_offset() -> f32 {
     }
 }
 
+/// Edge of the brand mark that anchors the window's leading corner off macOS
+/// (see [`window_mark`]). Between a chrome tile's 32px hit box and its 13px
+/// glyph: the mark paints no hover capsule, so what has to sit level with the
+/// tiles beside it is its *ink* — and solid art reads heavier than line work at
+/// equal size, hence short of the tile box rather than matching it.
+pub(crate) const WINDOW_MARK_SIZE: f32 = 20.;
+
+/// The "duo" mark — the same art the app icon and the About page carry — drawn
+/// at the leading edge of the title-bar row, or `None` on macOS.
+///
+/// macOS owns that corner: the traffic lights sit there, and [`TITLE_BAR_LEAD`]
+/// reserves them 80px. Everywhere else it is empty. The row's contents are the
+/// rail's controls at its *right* end and the window chrome at the far side, so
+/// the window's leading corner — the slot Windows reads as the app's identity,
+/// filled by Explorer, VS Code and Zed alike — held nothing at all, which comes
+/// across as unfinished rather than restrained.
+///
+/// Drawn, never clicked. It is not a menu button, so it stays out of the tile
+/// rhythm (no hover capsule) and deliberately takes no `occlude()`: the row it
+/// lives in is a `WindowControlArea::Drag`, and letting the mark fall through to
+/// that keeps the strip grabbable instead of punching a dead 20px hole in it.
+/// Make a row that stands in for the title bar behave like one: drag it to move
+/// the window, double-click it to zoom.
+///
+/// Three rows do this. The rail's top zone sits level with the real bar but
+/// outside it (the bar only spans the column beside the rail), and the code and
+/// diff overlays each cover the bar with a header of their own drawn to its line.
+/// Without this they are all dead strips: 40px across the top of the window that
+/// look exactly like the caption and do nothing when you grab them.
+///
+/// Driven the way gpui-component's own `TitleBar` drives it — a press arms a
+/// flag and the first *move* starts the window move — so a plain click, and a
+/// double-click, still land intact. Note that on Windows the drag area maps to
+/// HTCAPTION and the OS claims the press before gpui hit-tests, so every button
+/// inside one of these rows needs an `occlude()` wrapper to get its clicks back.
+pub(crate) fn title_bar_drag(row: gpui::Stateful<gpui::Div>) -> gpui::Stateful<gpui::Div> {
+    let should_move = Rc::new(Cell::new(false));
+    row.window_control_area(gpui::WindowControlArea::Drag)
+        .on_mouse_down(gpui::MouseButton::Left, {
+            let should_move = should_move.clone();
+            move |_, _, _| should_move.set(true)
+        })
+        .on_mouse_up(gpui::MouseButton::Left, {
+            let should_move = should_move.clone();
+            move |_, _, _| should_move.set(false)
+        })
+        .on_mouse_move(move |_, window, _| {
+            if should_move.replace(false) {
+                window.start_window_move();
+            }
+        })
+        .on_double_click(|_, window, _| {
+            // gpui only implements `titlebar_double_click` on macOS — the trait
+            // method is an empty default everywhere else, so on Linux this row
+            // swallowed the double-click and nothing zoomed. `zoom_window` is the
+            // maximise toggle there (x11 `_NET_WM_STATE_MAXIMIZED_*`, wayland
+            // `set_maximized`), and what gpui-component's own `TitleBar` calls on
+            // Linux for exactly this reason. Windows needs neither: the row is a
+            // drag area, which maps to HTCAPTION, and the OS has already restored
+            // or maximised the window before this could run.
+            if cfg!(target_os = "linux") {
+                window.zoom_window();
+            } else {
+                window.titlebar_double_click();
+            }
+        })
+}
+
+pub(crate) fn window_mark() -> Option<impl IntoElement> {
+    if cfg!(target_os = "macos") {
+        return None;
+    }
+    // Decoded once and shared: the title bar re-renders on every cursor blink,
+    // and building a fresh `Image` per frame would re-copy the PNG and miss
+    // gpui's image cache, which is keyed on the image's identity.
+    static LOGO: std::sync::OnceLock<Arc<gpui::Image>> = std::sync::OnceLock::new();
+    let logo = LOGO
+        .get_or_init(|| {
+            Arc::new(gpui::Image::from_bytes(
+                gpui::ImageFormat::Png,
+                include_bytes!("../../assets/logo@256.png").to_vec(),
+            ))
+        })
+        .clone();
+    Some(img(logo).size(px(WINDOW_MARK_SIZE)).flex_shrink_0())
+}
+
 /// One tab: a split-pane tree plus an optional user-assigned name. Settings is
 /// no longer a tab — it's a full-window overlay (`Tty7App::settings`), so every
 /// tab is a real terminal tab.
@@ -843,10 +932,16 @@ impl Tty7App {
             // First run (no session file): the very first terminal has no
             // predecessor to inherit from, so start in the app's current
             // directory (None → default behavior).
-            None => {
-                let first = new_terminal(font_size, None, None, None, window, cx);
-                (vec![Tab::new(Pane::leaf(first))], 0)
-            }
+            None => match new_terminal(font_size, None, None, None, window, cx) {
+                Ok(first) => (vec![Tab::new(Pane::leaf(first))], 0),
+                // The daemon we just tried to start isn't answering. A window
+                // with no tabs is a legal state (it shows the home page), and
+                // far better than taking the launch down over it.
+                Err(e) => {
+                    log::error!("first terminal failed to start: {e}");
+                    (Vec::new(), 0)
+                }
+            },
             // A saved session (with tabs, or an empty home-page state): rebuild it
             // the same way a daemon restart does.
             some => tabs_from_session(some, font_size, window, cx),
@@ -1265,7 +1360,13 @@ impl Tty7App {
             return;
         };
         let alive = alive_panes();
-        let pane = session_to_pane(&st.pane, &alive, self.font_size, window, cx);
+        let Some(pane) = session_to_pane(&st.pane, &alive, self.font_size, window, cx) else {
+            // Nothing came back (an unreachable daemon). Put the entry back so
+            // the tab is still reopenable once the daemon is up again.
+            window.push_notification("Could not reopen the tab: no terminal started", cx);
+            self.closed.push(st);
+            return;
+        };
         // Leaving the current tab for the reopened one; snapshot its focused
         // pane so switching back restores it (same as `activate`).
         self.remember_active_pane(window, cx);
@@ -2712,7 +2813,14 @@ impl Tty7App {
                 .focused_or_first(window, cx)
                 .and_then(|leaf| leaf.read(cx).local_cwd())
         });
-        let tab = new_terminal(self.font_size, cwd, None, shell, window, cx);
+        let tab = match new_terminal(self.font_size, cwd, None, shell, window, cx) {
+            Ok(view) => view,
+            Err(e) => {
+                log::error!("new tab spawn failed: {e}");
+                window.push_notification(format!("Could not open a terminal: {e}"), cx);
+                return;
+            }
+        };
         // Leaving the current tab for the new one; snapshot its focused pane
         // so switching back restores it (same as `activate`).
         self.remember_active_pane(window, cx);
@@ -2826,7 +2934,14 @@ impl Tty7App {
             }
         } else {
             let shell = target.read(cx).shell_spec();
-            new_terminal(self.font_size, cwd, None, shell, window, cx)
+            match new_terminal(self.font_size, cwd, None, shell, window, cx) {
+                Ok(view) => view,
+                Err(e) => {
+                    log::error!("split spawn failed: {e}");
+                    window.push_notification(format!("Could not split the pane: {e}"), cx);
+                    return;
+                }
+            }
         };
         if let Some(tab) = self.tabs.get_mut(self.active) {
             if tab.pane.split_leaf(&target, axis, new.clone()) {
@@ -3368,7 +3483,14 @@ impl Tty7App {
         window: &mut Window,
         cx: &mut Context<Self>,
     ) {
-        let view = new_terminal(self.font_size, Some(wt.path), None, None, window, cx);
+        let view = match new_terminal(self.font_size, Some(wt.path), None, None, window, cx) {
+            Ok(view) => view,
+            Err(e) => {
+                log::error!("worktree tab spawn failed: {e}");
+                window.push_notification(format!("Could not open a terminal: {e}"), cx);
+                return;
+            }
+        };
         self.remember_active_pane(window, cx);
         self.maximized = None;
         let insert_at = self.new_tab_insert_at(cx);
@@ -5198,6 +5320,26 @@ impl Render for Tty7App {
         } else {
             (Some(title_bar), None)
         };
+        // And where the overlays hang. Normally on the terminal column, which they
+        // fill: the bar is that column's first child, so an `inset_0` overlay
+        // covers it and the overlay's own header row lands *on* the caption line —
+        // which is what both headers are drawn for (title-bar height, the bar's
+        // insets, a full-size chrome tile for their one control).
+        //
+        // With the bar hoisted, a column-anchored overlay starts 40px down and its
+        // header sits one row too low: level with the panel's tab row instead of
+        // with the caption. So it hangs on the row that owns the bar instead,
+        // inset from the right by the panel's width — covering the bar's band over
+        // the terminal column (which carries nothing there but the drag region, or
+        // the rail's controls while it's collapsed: exactly what an overlay covers
+        // with the panel closed) and stopping short of the panel, so the ─ ▢ ✕
+        // group and the corner chrome keep their own surface and their clicks.
+        let (column_overlays, hoisted_overlays) = if panel_below_title_bar {
+            (Vec::new(), overlays)
+        } else {
+            (overlays, Vec::new())
+        };
+        let panel_px = self.right_panel_px(window, cx);
         // The terminal column, and the anchor for both overlays: they fill it —
         // and, since the panel is a sibling rather than a child, stop short of the
         // panel for free. With the bar spanning above, they stop short of it too,
@@ -5211,7 +5353,7 @@ impl Render for Tty7App {
             .relative()
             .when_some(column_title_bar, |this, bar| this.child(bar))
             .child(body_area)
-            .children(overlays);
+            .children(column_overlays);
         let panel_row = div()
             .flex_1()
             .min_h_0()
@@ -5233,6 +5375,8 @@ impl Render for Tty7App {
                     .min_w_0()
                     .flex()
                     .flex_col()
+                    // The containing block for the hoisted overlays below.
+                    .relative()
                     .child(
                         // The bar's own band over the panel, painted in the panel's
                         // surface so the column still reads as one continuous
@@ -5265,6 +5409,19 @@ impl Render for Tty7App {
                             .child(bar),
                     )
                     .child(panel_row)
+                    // Last child, so they paint over both the bar and the column.
+                    // Each overlay is `absolute().inset_0()` against this wrapper,
+                    // which is the only thing that has to know where the panel
+                    // starts.
+                    .children(hoisted_overlays.into_iter().map(|overlay| {
+                        div()
+                            .absolute()
+                            .top_0()
+                            .left_0()
+                            .bottom_0()
+                            .right(px(panel_px))
+                            .child(overlay)
+                    }))
                     .into_any_element(),
                 None => panel_row.into_any_element(),
             })
@@ -5693,7 +5850,12 @@ fn tabs_from_session(
     let alive = alive_panes();
     let mut tabs: Vec<Tab> = Vec::with_capacity(session.tabs.len());
     for st in &session.tabs {
-        let pane = session_to_pane(&st.pane, &alive, font_size, window, cx);
+        // A tab whose every leaf failed to come back has nothing to show; drop
+        // it rather than restore an empty frame (or, worse, abort the launch).
+        let Some(pane) = session_to_pane(&st.pane, &alive, font_size, window, cx) else {
+            log::error!("dropping a restored tab: no pane in it could be started");
+            continue;
+        };
         tabs.push(Tab {
             pane,
             name: st.name.clone(),
@@ -5707,8 +5869,9 @@ fn tabs_from_session(
             sidebar_group: std::cell::RefCell::new(st.sidebar_group.clone()),
         });
     }
-    // Clamp the saved active index into the rebuilt range.
-    let active = session.active.min(tabs.len() - 1);
+    // Clamp the saved active index into the rebuilt range (which can be empty
+    // when nothing restored).
+    let active = session.active.min(tabs.len().saturating_sub(1));
     (tabs, active)
 }
 
@@ -5716,13 +5879,17 @@ fn tabs_from_session(
 /// `pane_id` is still alive in the daemon re-`attach`es (process + scrollback
 /// intact); otherwise it spawns a fresh shell in the saved cwd. `alive` is the
 /// daemon's current pane set, computed once by the caller.
+///
+/// `None` when nothing under this node could be started (an unreachable
+/// daemon): restore drops what it can't rebuild instead of leaving `Empty`
+/// nodes — which every tree operation ignores — in a live tab.
 fn session_to_pane(
     sp: &SessionPane,
     alive: &std::collections::HashSet<u64>,
     font_size: f32,
     window: &mut Window,
     cx: &mut Context<Tty7App>,
-) -> Pane {
+) -> Option<Pane> {
     match sp {
         SessionPane::Leaf {
             cwd,
@@ -5743,7 +5910,7 @@ fn session_to_pane(
                 if let Some(spec) = ssh_spec.clone() {
                     let resolved = crate::ui::ssh_connect::resolve_persisted_ssh_spec(spec, cx);
                     match new_terminal_native(font_size, cwd.clone(), resolved, window, cx) {
-                        Ok(view) => return Pane::leaf(view),
+                        Ok(view) => return Some(Pane::leaf(view)),
                         // Keep restore alive: fall through to a local shell in
                         // this slot rather than aborting startup.
                         Err(e) => log::error!("restoring native SSH pane failed: {e}"),
@@ -5752,7 +5919,13 @@ fn session_to_pane(
             }
             // A shell pick isn't persisted in the session, so a stale pane that
             // must respawn comes back on the default shell.
-            let view = new_terminal(font_size, cwd.clone(), restore, None, window, cx);
+            let view = match new_terminal(font_size, cwd.clone(), restore, None, window, cx) {
+                Ok(view) => view,
+                Err(e) => {
+                    log::error!("restoring pane failed: {e}");
+                    return None;
+                }
+            };
             // A pane that could NOT re-attach lost its running agent with the
             // daemon; when we captured that agent's native session id, hand
             // the fresh shell its resume command so the conversation picks up
@@ -5766,20 +5939,32 @@ fn session_to_pane(
             {
                 view.read(cx).run_command_line(&cmd);
             }
-            Pane::leaf(view)
+            Some(Pane::leaf(view))
         }
         SessionPane::Split { axis, ratio, a, b } => {
             let axis = match axis {
                 SessionAxis::Horizontal => Axis::Horizontal,
                 SessionAxis::Vertical => Axis::Vertical,
             };
-            let a = session_to_pane(a, alive, font_size, window, cx);
-            let b = session_to_pane(b, alive, font_size, window, cx);
-            Pane::split_node(axis, *ratio, a, b)
+            // One side failing collapses the split onto the survivor, exactly
+            // as closing that pane by hand would.
+            match (
+                session_to_pane(a, alive, font_size, window, cx),
+                session_to_pane(b, alive, font_size, window, cx),
+            ) {
+                (Some(a), Some(b)) => Some(Pane::split_node(axis, *ratio, a, b)),
+                (Some(only), None) | (None, Some(only)) => Some(only),
+                (None, None) => None,
+            }
         }
     }
 }
 
+/// Build a shell-backed terminal view, wiring the per-pane subscriptions every
+/// pane needs. Fallible: the daemon can refuse the spawn (it died, it's
+/// wedged, the shell doesn't exist), and every caller here runs inside a gpui
+/// input callback, where a panic can't unwind and would abort the app instead
+/// of surfacing the failure. Report it, don't `expect` it.
 fn new_terminal(
     font_size: f32,
     working_directory: Option<std::path::PathBuf>,
@@ -5787,10 +5972,10 @@ fn new_terminal(
     shell: Option<ShellSpec>,
     window: &mut Window,
     cx: &mut Context<Tty7App>,
-) -> Entity<TerminalView> {
+) -> anyhow::Result<Entity<TerminalView>> {
+    let parts = TerminalView::spawn_shell_terminal(working_directory, restore_pane, shell)?;
     let view = cx.new(|cx| {
-        let mut view = TerminalView::new(working_directory, restore_pane, shell, window, cx)
-            .expect("failed to start terminal");
+        let mut view = TerminalView::from_shell_parts(parts, window, cx);
         // Inherit the current global font size so new panes match existing ones.
         view.font_size = px(font_size);
         view
@@ -5816,7 +6001,7 @@ fn new_terminal(
     )
     .detach();
     watch_pane_focus(&view, window, cx);
-    view
+    Ok(view)
 }
 
 /// Re-render the app whenever `view` takes focus. Nothing else does this: a

src/ui/code_editor.rs

@@ -801,7 +801,7 @@ impl Tty7App {
     /// every buffer that was ever opened. Sits on the title bar's line and matches
     /// its height, so the editor's top edge lines up with the panel's tab row and
     /// the rail's controls across the window.
-    fn render_editor_header(&self, cx: &mut Context<Self>) -> gpui::Div {
+    fn render_editor_header(&self, cx: &mut Context<Self>) -> gpui::Stateful<gpui::Div> {
         let active = self.tab_code().and_then(|c| c.active_file());
         let name = active.map(|f| f.label());
         let dirty = active.is_some_and(|f| f.dirty);
@@ -816,7 +816,10 @@ impl Tty7App {
         } else {
             crate::ui::app::TITLE_BAR_LEAD
         };
-        h_flex()
+        // The overlay covers the real title bar, so this row inherits its drag and
+        // zoom gestures — otherwise opening a file turns the top of the window into
+        // a strip that looks like the caption and can't move it.
+        crate::ui::app::title_bar_drag(h_flex().id("editor-header"))
             .flex_none()
             .h(px(crate::ui::app::TITLE_BAR_HEIGHT))
             .items_center()
@@ -847,22 +850,27 @@ impl Tty7App {
                 )
             })
             .child(
-                crate::ui::tab_strip::chrome_tile_sized(
-                    // This header is the title bar's own height and sits flush
-                    // with it, so its one control is a full chrome tile — not the
-                    // half-size one it used to be, which read as a different
-                    // class of button on the same line.
-                    Button::new("editor-panel-close").icon(Icon::new(IconName::Close)),
-                    crate::ui::app::TILE_SIZE,
-                    crate::ui::app::TILE_GLYPH_LINE,
-                    false,
-                    cx,
-                )
-                .rounded_lg()
-                .tooltip("Back to Terminal (Esc)")
-                .on_click(cx.listener(|this, _, window, cx| {
-                    this.toggle_code_panel(window, cx);
-                })),
+                // `occlude()` for the same reason the title bar's own tiles carry
+                // it: this row is a `WindowControlArea::Drag`, which on Windows is
+                // HTCAPTION, and the OS takes the press before gpui hit-tests.
+                div().occlude().flex_shrink_0().child(
+                    crate::ui::tab_strip::chrome_tile_sized(
+                        // This header is the title bar's own height and sits flush
+                        // with it, so its one control is a full chrome tile — not the
+                        // half-size one it used to be, which read as a different
+                        // class of button on the same line.
+                        Button::new("editor-panel-close").icon(Icon::new(IconName::Close)),
+                        crate::ui::app::TILE_SIZE,
+                        crate::ui::app::TILE_GLYPH_LINE,
+                        false,
+                        cx,
+                    )
+                    .rounded_lg()
+                    .tooltip("Back to Terminal (Esc)")
+                    .on_click(cx.listener(|this, _, window, cx| {
+                        this.toggle_code_panel(window, cx);
+                    })),
+                ),
             )
     }
 

src/ui/diff_overlay.rs

@@ -327,7 +327,10 @@ impl Tty7App {
         } else {
             crate::ui::app::TITLE_BAR_LEAD
         };
-        h_flex()
+        // Standing in for the title bar means carrying its gestures too: the
+        // overlay covers the real bar, so without this the whole top of the window
+        // stops moving it while a diff is up.
+        crate::ui::app::title_bar_drag(h_flex().id("diff-overlay-header"))
             .flex_shrink_0()
             .h(px(crate::ui::app::TITLE_BAR_HEIGHT))
             .pl(px(lead))
@@ -355,38 +358,42 @@ impl Tty7App {
             // click target back to the whole tree — otherwise the only way out
             // of a focused view would be to close and re-open the overlay.
             .when_some(focused_name(overlay), |bar, name| {
+                // Wrapped like every other control on a drag row — see the header's
+                // own note: HTCAPTION would otherwise swallow the click on Windows.
                 bar.child(
-                    h_flex()
-                        .id("diff-overlay-unfocus")
-                        .items_center()
-                        .gap_1()
-                        .px_1p5()
-                        .py_0p5()
-                        .rounded_md()
-                        .cursor_pointer()
-                        .hover(|s| s.bg(cx.theme().list_hover))
-                        .on_click(cx.listener(|this, _, _window, cx| {
-                            let active = this.active;
-                            if let Some(overlay) = this
-                                .tabs
-                                .get_mut(active)
-                                .and_then(|t| t.diff_overlay.as_mut())
-                            {
-                                overlay.focus = None;
-                                cx.notify();
-                            }
-                        }))
-                        .child(
-                            Icon::new(IconName::ChevronLeft)
-                                .small()
-                                .text_color(cx.theme().muted_foreground),
-                        )
-                        .child(
-                            div()
-                                .text_xs()
-                                .font_family(self.font_family.clone())
-                                .child(name),
-                        ),
+                    div().occlude().flex_shrink_0().child(
+                        h_flex()
+                            .id("diff-overlay-unfocus")
+                            .items_center()
+                            .gap_1()
+                            .px_1p5()
+                            .py_0p5()
+                            .rounded_md()
+                            .cursor_pointer()
+                            .hover(|s| s.bg(cx.theme().list_hover))
+                            .on_click(cx.listener(|this, _, _window, cx| {
+                                let active = this.active;
+                                if let Some(overlay) = this
+                                    .tabs
+                                    .get_mut(active)
+                                    .and_then(|t| t.diff_overlay.as_mut())
+                                {
+                                    overlay.focus = None;
+                                    cx.notify();
+                                }
+                            }))
+                            .child(
+                                Icon::new(IconName::ChevronLeft)
+                                    .small()
+                                    .text_color(cx.theme().muted_foreground),
+                            )
+                            .child(
+                                div()
+                                    .text_xs()
+                                    .font_family(self.font_family.clone())
+                                    .child(name),
+                            ),
+                    ),
                 )
             })
             .when(
@@ -438,21 +445,23 @@ impl Tty7App {
             )
             .child(div().flex_1())
             .child(
-                crate::ui::tab_strip::chrome_tile_sized(
-                    // Explicit tile, not `.small()`: this bar stands in for the
-                    // title bar while the overlay is up, so its close control is
-                    // the same tile the title bar's controls are.
-                    Button::new("diff-overlay-close").icon(Icon::new(IconName::Close)),
-                    crate::ui::app::TILE_SIZE,
-                    crate::ui::app::TILE_GLYPH_LINE,
-                    false,
-                    cx,
-                )
-                .rounded_lg()
-                .tooltip("Close Diff (Esc)")
-                .on_click(cx.listener(|this, _, window, cx| {
-                    this.close_diff_overlay(window, cx);
-                })),
+                div().occlude().flex_shrink_0().child(
+                    crate::ui::tab_strip::chrome_tile_sized(
+                        // Explicit tile, not `.small()`: this bar stands in for the
+                        // title bar while the overlay is up, so its close control is
+                        // the same tile the title bar's controls are.
+                        Button::new("diff-overlay-close").icon(Icon::new(IconName::Close)),
+                        crate::ui::app::TILE_SIZE,
+                        crate::ui::app::TILE_GLYPH_LINE,
+                        false,
+                        cx,
+                    )
+                    .rounded_lg()
+                    .tooltip("Close Diff (Esc)")
+                    .on_click(cx.listener(|this, _, window, cx| {
+                        this.close_diff_overlay(window, cx);
+                    })),
+                ),
             )
     }
 

src/ui/file_tree.rs

@@ -1156,6 +1156,7 @@ impl Tty7App {
         let is_dir = row.entry.is_dir;
         let selected = self.tab_code().and_then(|c| c.selected.as_deref()) == Some(&*path);
         let muted = cx.theme().muted_foreground;
+        let sf = cx.global::<crate::ui::presets::Surfaces>().popover;
         // Unsaved edits used to be visible on the editor's file tabs; with those
         // gone the tree is the only place an open buffer is represented, so it has
         // to carry the dirty marker or unsaved work becomes invisible.
@@ -1207,11 +1208,15 @@ impl Tty7App {
             .py_1()
             .rounded(cx.theme().radius)
             .cursor_pointer()
-            // Soft inset-pill highlight on the content surface.
-            .when(selected, |d| d.bg(cx.theme().accent))
-            .when(!selected, |d| {
-                d.hover(|s| s.bg(cx.theme().accent.opacity(0.5)))
-            })
+            // Soft inset-pill highlight on the content surface. The tree paints on
+            // `popover` (see the container below), so this is that surface's
+            // ladder — read explicitly rather than through `Theme::accent`, which
+            // is gpui-component's name for a row highlight and says nothing about
+            // which surface it was anchored to. Hover was `accent.opacity(0.5)`; a
+            // ladder rung is a real colour, so it doesn't change meaning depending
+            // on what it lands on.
+            .when(selected, |d| d.bg(gpui::rgb(sf.selected)))
+            .when(!selected, |d| d.hover(|s| s.bg(gpui::rgb(sf.hover))))
             // Folders take the full foreground, files the muted tone — a neutral
             // weight difference, no hue, so the tree keeps the terminal's calm.
             .child(Icon::new(icon).xsmall().text_color(if is_dir {

src/ui/forwards.rs

@@ -240,6 +240,7 @@ impl Tty7App {
     ) -> Stateful<Div> {
         let theme = cx.theme();
         let muted = theme.muted_foreground;
+        let sf = cx.global::<crate::ui::presets::Surfaces>().sidebar;
         let letter = match forward.kind {
             SshForwardKind::Local => "L",
             SshForwardKind::Remote => "R",
@@ -277,7 +278,7 @@ impl Tty7App {
             .py(px(3.))
             .rounded(px(5.))
             .cursor_pointer()
-            .hover(|s| s.bg(theme.sidebar_accent.opacity(0.55)))
+            .hover(|s| s.bg(gpui::rgb(sf.hover)))
             .on_click(cx.listener(move |this, _, window, cx| {
                 this.edit_managed_forward(forward_for_edit.clone(), window, cx)
             }))
@@ -357,6 +358,9 @@ impl Tty7App {
     fn forward_form(&self, pane_id: u64, cx: &mut Context<Self>) -> Div {
         let theme = cx.theme();
         let muted = theme.muted_foreground;
+        // The form is inside the right panel, i.e. on the sunk rail — not on the
+        // settings sheet the segmented control otherwise assumes.
+        let sf = cx.global::<crate::ui::presets::Surfaces>().sidebar;
         let kind = self.loopback_panel.mf_kind;
         let editing = self.loopback_panel.mf_editing.is_some();
         let selected = match kind {
@@ -393,7 +397,8 @@ impl Tty7App {
             .pt(px(6.))
             .pb(px(2.))
             .gap(px(5.))
-            .child(self.segmented(
+            .child(self.segmented_on(
+                sf,
                 "ssh-managed-forward-kind",
                 &["Local", "Remote", "Dynamic"],
                 selected,

src/ui/home.rs

@@ -297,8 +297,10 @@ impl Tty7App {
             )
         };
         // The established popup language: a solid 10px-radius panel with inset
-        // soft-grey pill highlights — no translucency, no saturated accent.
-        let hover_fill = cx.theme().accent.opacity(0.6);
+        // soft-grey pill highlights — no translucency, no saturated accent. The
+        // panel is a popover, so its rows read that ladder's hover rung; the 0.6
+        // alpha this replaces made the fill depend on whatever showed through.
+        let hover_fill = gpui::rgb(cx.global::<crate::ui::presets::Surfaces>().popover.hover);
 
         let mut panel = v_flex()
             .w(px(360.))

src/ui/presets.rs

@@ -1,7 +1,7 @@
 //! The theme system: the serializable [`Theme`] seed model, the derived
-//! shell-chrome [`Neutrals`], the [`Themes`] registry, and the loaders that turn
-//! built-in tables, user YAML files, and imported iTerm2 schemes into concrete
-//! themes.
+//! shell-chrome [`Neutrals`], the interaction-state [`Surface`] ladders, the
+//! [`Themes`] registry, and the loaders that turn built-in tables, user YAML
+//! files, and imported iTerm2 schemes into concrete themes.
 //!
 //! A theme is a **minimal seed** — a background (solid or gradient), a
 //! foreground, one accent, an optional cursor/selection, and the ANSI-16
@@ -15,6 +15,14 @@
 //! in an iTerm2 `*.itermcolors` scheme, which the loader imports on the fly. A
 //! theme's light/dark brightness is *inferred* from its background luminance —
 //! there is no `dark` field to set.
+//!
+//! # Interaction state
+//!
+//! Resting / hover / selected / pressed are a **first-class part of the theme**,
+//! not something each widget re-derives. [`Theme::surface`] returns the state
+//! ladder for whatever surface a widget paints on, and every rung is derived to
+//! hit a *contrast ratio* against that surface rather than a fixed blend ratio —
+//! see [`state`] for why that distinction is the whole point.
 
 use std::path::PathBuf;
 
@@ -87,6 +95,10 @@ pub struct Theme {
 
 /// The shell-chrome palette derived from a theme's seed. Consumed by
 /// `apply_theme` to paint gpui-component's `Theme`.
+///
+/// These are the theme's *static* colors — the ones that mean the same thing
+/// wherever they appear. Anything that varies with interaction state lives in a
+/// [`Surface`] instead.
 #[derive(Debug, Clone)]
 pub struct Neutrals {
     pub background: u32,
@@ -99,12 +111,148 @@ pub struct Neutrals {
     pub caret: u32,
     pub selection: u32,
     pub sidebar: u32,
-    pub sidebar_sel: u32,
     pub sidebar_fg: u32,
-    pub list_active: u32,
-    pub list_hover: u32,
+    /// The seed accent, nudged until it can carry ink — see [`legible_accent`].
+    pub accent: u32,
 }
 
+/// One semantic colour in the three shapes the UI actually needs it in.
+///
+/// Splitting them is not ceremony: a red that is legible as *text* on the
+/// background is a different red from one that works as a filled button, and the
+/// text on that button is a third. Collapsing them is how a danger button ends up
+/// with unreadable text, or a warning label ends up below AA.
+#[derive(Debug, Clone, Copy)]
+pub struct Semantic {
+    /// Text (or a small solid mark) on the window background. WCAG AA, 4.5:1.
+    pub ink: u32,
+    /// A filled chip or button. The non-text floor, 3:1.
+    pub fill: u32,
+    /// Text on top of `fill`.
+    pub on_fill: u32,
+}
+
+/// The status palette, derived from the theme's **own ANSI-16** rather than from
+/// a fixed set of brand colours.
+///
+/// Every theme already ships a red, green, yellow and cyan — they are what the
+/// terminal in the same window paints with. Until this existed, gpui-component's
+/// stock Tailwind values (`red-400`, `yellow-400`, `green-400`) were used
+/// instead, which meant two unrelated reds on screen at once — `#ff5555` in the
+/// terminal and `#f87171` on the delete button, on Dracula — and, on the light
+/// themes, a danger colour at 2.45:1 that cleared no contrast floor at all.
+///
+/// Each is conditioned by [`legible_ink`], so a seed too pale or too dark for its
+/// role is deepened along its own hue rather than swapped for something foreign.
+#[derive(Debug, Clone)]
+pub struct Semantics {
+    pub danger: Semantic,
+    pub warning: Semantic,
+    pub success: Semantic,
+    pub info: Semantic,
+    /// Links. Distinct from `info` only in intent, but it is the field
+    /// gpui-component's markdown renderer reads, and left unset it resolves to
+    /// the body text colour — a link that looks exactly like prose.
+    pub link: Semantic,
+}
+
+/// The contrast targets that define how loud each interaction state reads.
+///
+/// **These four numbers are the app's only knobs for state prominence.** They
+/// exist because the alternative — a fixed `mix(bg, fg, t)` per state, which is
+/// what this file used to do — makes the *perceived* step depend on the theme.
+/// The old ladder (`hover` 0.09, `sidebar_sel` 0.12, `list_active` 0.17) put
+/// selected-vs-resting anywhere from 1.20:1 (Catppuccin Latte) to 1.47:1
+/// (Dracula), and the segmented control — which read gpui-component's stock
+/// `input` grey instead of the ladder at all — landed at **1.03:1 on Dracula**,
+/// i.e. invisible. See issue #197.
+///
+/// A ratio target removes the theme from the equation: every theme lands on the
+/// same perceived step, so tuning taste here retunes the whole app at once and
+/// no theme can be an outlier.
+///
+/// `SELECTED` is 1.70 because that is where the already-signed-off Dracula
+/// highlight sits (`mix(bg, fg, 0.17)` ≈ `#4b4d56`, 1.72:1) — the value the
+/// palette and menu look was tuned against. Anchoring *to* it keeps that look
+/// and pulls the light themes, which were as low as 1.20:1, up to match.
+pub mod state {
+    /// Pointer feedback. Deliberately a whisper: it answers the mouse without
+    /// competing with the selection it may be sitting next to.
+    pub const HOVER: f32 = 1.18;
+    /// The resting selection. Never the *only* signal — see [`super::Surface`].
+    pub const SELECTED: f32 = 1.70;
+    /// Held down. One step past selected so pressing a selected item still reads.
+    pub const PRESSED: f32 = 2.10;
+    /// Resting label text. 4.6:1 keeps a de-emphasised label at WCAG AA on every
+    /// theme; the fixed `mix(fg, bg, 0.42)` it replaces drifted with the seed.
+    pub const TEXT_RESTING: f32 = 4.6;
+}
+
+/// The interaction-state ladder for one painting surface: the fills for each
+/// state plus the paired label colors.
+///
+/// # Both channels, always
+///
+/// A fill alone does not communicate selection. The app learned this the hard
+/// way in three separate places — `tab_strip`'s active chip, `tab_strip`'s
+/// chrome tiles and the settings sidebar each grew a hand-written
+/// fill-plus-text-color pair, while every site that *hadn't* been hand-fixed
+/// (segmented controls, the SSH profile list) shipped a fill and nothing else
+/// and could not be read. So the text colors ride along in this struct: take a
+/// `Surface`, take both channels.
+///
+/// * **Fill** answers *which one* — it locates the selection in the row.
+/// * **Text** (`text_selected` + `FontWeight::MEDIUM` vs `text_resting`)
+///   answers *that this is it* — it survives a low-contrast fill, an oddly
+///   seeded imported theme, and a color-blind reader.
+///
+/// A keyboard-driven single cursor (the command palette, a context menu) can get
+/// away with the fill alone because the eye tracks the one thing that moves.
+/// A *static* choice among visible siblings cannot.
+#[derive(Debug, Clone, Copy)]
+pub struct Surface {
+    /// The surface itself — what a resting item paints on (i.e. no fill).
+    pub base: u32,
+    pub hover: u32,
+    pub selected: u32,
+    pub pressed: u32,
+    /// Label color for a resting/unselected item on this surface.
+    pub text_resting: u32,
+    /// Label color for the selected item. Pair it with `FontWeight::MEDIUM`.
+    pub text_selected: u32,
+}
+
+/// Every surface the shell actually paints interactive rows on, published as a
+/// GPUI global by `apply_theme` so a render pass can read the ladder without
+/// re-resolving (and cloning) the theme registry every frame.
+///
+/// Which surface a widget picks matters: a menu row sits on `popover`, not on
+/// the window background, and a ladder anchored to the wrong surface is exactly
+/// how the context-menu highlight ended up at 1.20:1 while claiming to be the
+/// same 0.17 mix that reads fine on the window.
+#[derive(Debug, Clone)]
+pub struct Surfaces {
+    /// The window background — settings sheets, panels, the terminal ground.
+    pub window: Surface,
+    /// The sunk sidebar rail.
+    pub sidebar: Surface,
+    /// Elevated surfaces: menus, dropdowns, the command palette.
+    pub popover: Surface,
+}
+
+impl Global for Surfaces {}
+
+/// The active theme's contrast-conditioned accent (see [`legible_accent`]),
+/// published so a render pass can reach it without cloning the theme registry.
+///
+/// Deliberately its own global rather than a field on [`Surfaces`]: the accent is
+/// not a surface, and it has exactly one job — ink that must be *noticed* (the
+/// caret, the focus ring, a switch's checked track). Every neutral fill in the
+/// app comes from a `Surface`; this is the one thing that doesn't.
+pub struct ActiveAccent(pub u32);
+
+impl Global for ActiveAccent {}
+
 impl Theme {
     /// The representative solid background color.
     pub fn background_color(&self) -> u32 {
@@ -125,15 +273,87 @@ impl Theme {
             border: mix(bg, fg, 0.16),
             secondary: mix(bg, fg, 0.09),
             muted: mix(bg, fg, 0.06),
-            muted_foreground: mix(fg, bg, 0.42),
+            muted_foreground: dim(fg, bg, state::TEXT_RESTING),
             popover: mix(bg, fg, 0.05),
             caret: self.caret.unwrap_or(self.accent),
             selection: self.selection.unwrap_or_else(|| mix(bg, fg, 0.20)),
             sidebar: mix(bg, fg, 0.03),
-            sidebar_sel: mix(bg, fg, 0.12),
             sidebar_fg: mix(fg, bg, 0.28),
-            list_active: mix(bg, fg, 0.17),
-            list_hover: mix(bg, fg, 0.09),
+            accent: legible_accent(bg, self.accent),
+        }
+    }
+
+    /// The interaction-state ladder for content painted on `base`.
+    ///
+    /// Every rung blends `base` toward the (legibility-guaranteed) foreground
+    /// until it clears its [`state`] contrast target *against `base`* — so the
+    /// direction is "toward the text" by construction on light and dark themes
+    /// alike. The old fixed-mix ladder had no such guarantee: because the
+    /// segmented control's fill came from a stock grey rather than the theme,
+    /// selecting a segment made it *darker* than its siblings on light themes
+    /// and *lighter* on dark ones, by accident of where `#2f2f2f` happened to
+    /// fall.
+    pub fn surface(&self, base: u32) -> Surface {
+        let bg = self.background_color();
+        let fg = legible_foreground(bg, self.foreground);
+        let selected = raise(base, fg, state::SELECTED);
+        Surface {
+            base,
+            hover: raise(base, fg, state::HOVER),
+            selected,
+            pressed: raise(base, fg, state::PRESSED),
+            // Dimmed from the foreground until it is merely AA-readable on this
+            // surface, rather than a fixed blend — a resting label must stay
+            // legible on an imported theme nobody vetted, too.
+            text_resting: dim(fg, base, state::TEXT_RESTING),
+            // Measured against the *selected fill*, not the surface: that fill is
+            // the ground this particular label actually sits on. See `ink_on`.
+            text_selected: ink_on(selected, fg, state::TEXT_RESTING),
+        }
+    }
+
+    /// The status palette, built from this theme's own ANSI red/green/yellow/cyan.
+    ///
+    /// The normal (not bright) ANSI slots are the seeds: they are what the
+    /// terminal in the same window paints, so a danger marker and an error line
+    /// of shell output finally wear the same red. Where a slot is too pale or too
+    /// dark for a role, [`legible_ink`] deepens it along its own hue rather than
+    /// reaching for a colour the theme never declared.
+    pub fn semantics(&self) -> Semantics {
+        let bg = self.background_color();
+        let fg = legible_foreground(bg, self.foreground);
+        let ansi = |i: usize| -> u32 {
+            let (r, g, b) = self.ansi16[i];
+            (r as u32) << 16 | (g as u32) << 8 | b as u32
+        };
+        let build = |seed: u32| {
+            let fill = legible_ink(bg, seed, ACCENT_FLOOR);
+            Semantic {
+                ink: legible_ink(bg, seed, TEXT_FLOOR),
+                fill,
+                on_fill: ink_on(fill, fg, TEXT_FLOOR),
+            }
+        };
+        Semantics {
+            danger: build(ansi(1)),
+            success: build(ansi(2)),
+            warning: build(ansi(3)),
+            info: build(ansi(6)),
+            link: build(ansi(6)),
+        }
+    }
+
+    /// The ladders for all three surfaces the shell paints rows on.
+    pub fn surfaces(&self) -> Surfaces {
+        let m = self.neutrals();
+        let mut sidebar = self.surface(m.sidebar);
+        // The rail's resting label is a tuned value (a lighter 0.28 dim, so rows
+        // in a sunk column don't read as disabled), not the generic AA floor.
+        sidebar.text_resting = m.sidebar_fg;
+        Surfaces {
+            window: self.surface(m.background),
+            sidebar,
+            popover: self.surface(m.popover),
         }
     }
 
@@ -179,6 +399,109 @@ impl Theme {
     }
 }
 
+/// The shared bisection behind [`raise`] and [`dim`]: find the blend of `from`
+/// toward `toward` whose contrast against `from`-or-`toward` (whichever is the
+/// surface, passed as `against`) sits at `target`.
+///
+/// `against` must **not** sit strictly between the endpoints in luminance, or
+/// the ratio along the blend is V-shaped rather than monotone and a bisection
+/// would return an arbitrary one of the two answers. Every caller satisfies
+/// that: [`raise`] and [`dim`] pass one of the endpoints itself, and
+/// [`legible_accent`] passes the background, which an accent only reaches this
+/// code by being *close* to — while `fg` is guaranteed 4.5:1 away from it.
+fn bisect_contrast(from: u32, toward: u32, against: u32, target: f32) -> u32 {
+    // 12 halvings resolve t to ~0.0002 — far finer than an 8-bit channel step,
+    // so the result is exact in the only units that reach the screen.
+    const STEPS: u32 = 12;
+    let rising = contrast(toward, against) > contrast(from, against);
+    // Unreachable target (e.g. a 4.6:1 label floor on a surface whose own
+    // foreground only manages 4.5): clamp to the most extreme blend rather than
+    // returning something arbitrary from the middle of the range.
+    if rising && contrast(toward, against) <= target {
+        return toward;
+    }
+    if !rising && contrast(toward, against) >= target {
+        return toward;
+    }
+    let (mut lo, mut hi) = (0.0f32, 1.0f32);
+    for _ in 0..STEPS {
+        let m = 0.5 * (lo + hi);
+        let reached = if rising {
+            contrast(mix(from, toward, m), against) >= target
+        } else {
+            contrast(mix(from, toward, m), against) <= target
+        };
+        if reached { hi = m } else { lo = m }
+    }
+    mix(from, toward, hi)
+}
+
+/// Lift a fill off `base` toward `toward` (always the foreground) until it
+/// clears `target` contrast against `base`.
+///
+/// This is the primitive that replaced fixed `mix(bg, fg, t)` state colors: the
+/// caller names the perceived step it wants and gets it on every theme, instead
+/// of naming a blend and getting whatever step that theme's seed implies.
+fn raise(base: u32, toward: u32, target: f32) -> u32 {
+    bisect_contrast(base, toward, base, target)
+}
+
+/// Dim `ink` toward `surface` until it sits *at* `target` contrast against
+/// `surface` — a de-emphasised label that is still guaranteed readable, rather
+/// than a fixed blend whose ratio drifts with the seed.
+fn dim(ink: u32, surface: u32, target: f32) -> u32 {
+    bisect_contrast(ink, surface, surface, target)
+}
+
+/// The label color for text sitting on `fill`: the theme's foreground when it
+/// still clears `target` there, otherwise that foreground pushed *past* itself
+/// (toward white on a dark fill, black on a light one) until it does.
+///
+/// This exists because the fill ladder and the text channel pull against each
+/// other. Raising a fill toward the foreground necessarily moves the ground
+/// closer to the label it carries, and on a theme whose foreground isn't an
+/// extreme — Catppuccin Latte's `#4c4f69` is only 7.4:1 on its own background —
+/// a 1.70:1 selected fill drags the selected label down to 4.14:1, *below* the
+/// resting labels around it. A selection whose text is harder to read than its
+/// neighbours' is not a selection.
+///
+/// Pushing along the fg→extreme axis rather than snapping to pure black/white
+/// keeps the theme's ink hue; Latte's selected label becomes a deeper version of
+/// the same blue-grey, not a foreign pure black.
+///
+/// Three tiers, in order of how much of the theme they preserve: the foreground
+/// itself, then the foreground deepened along its own side, then — only when that
+/// side simply cannot reach the target — the opposite extreme. That last tier is
+/// not hypothetical: the Light theme's danger fill is `#d1242f`, a mid-dark red
+/// against which even *pure black* tops out at 3.96:1. White text on a dark red
+/// button is the right answer there, and it is only reachable by looking the
+/// other way.
+fn ink_on(fill: u32, fg: u32, target: f32) -> u32 {
+    if contrast(fg, fill) >= target {
+        return fg;
+    }
+    // Push *away* from the fill along the axis the foreground already sits on —
+    // darker ink gets darker, lighter ink lighter. Choosing the extreme by the
+    // fill's own brightness instead is wrong at the midpoint: Latte's `#b8bac6`
+    // fill reads as "dark" to a `< 0.5` luminance test, which sends its already
+    // dark ink toward white and *lowers* the contrast it was called to raise.
+    let near = if relative_luminance(fg) < relative_luminance(fill) {
+        0x000000
+    } else {
+        0xffffff
+    };
+    let deepened = bisect_contrast(fg, near, fill, target);
+    if contrast(deepened, fill) >= target {
+        return deepened;
+    }
+    // The foreground's own side is exhausted. Take whichever extreme reads best.
+    if contrast(fill, 0xffffff) >= contrast(fill, 0x000000) {
+        0xffffff
+    } else {
+        0x000000
+    }
+}
+
 /// Blend `a` toward `b` by `t` (0.0 = all `a`, 1.0 = all `b`), per channel.
 pub(crate) fn mix(a: u32, b: u32, t: f32) -> u32 {
     let (ar, ag, ab) = (a >> 16 & 0xff, a >> 8 & 0xff, a & 0xff);
@@ -211,6 +534,15 @@ fn relative_luminance(c: u32) -> f32 {
     0.2126 * chan(c >> 16 & 0xff) + 0.7152 * chan(c >> 8 & 0xff) + 0.0722 * chan(c & 0xff)
 }
 
+/// The largest per-channel difference between two colors (0…255). A crude but
+/// hue-aware "are these the same colour" check — contrast alone can't tell red
+/// from green, since they can share a luminance.
+#[cfg(test)]
+fn channel_distance(a: u32, b: u32) -> u32 {
+    let d = |sh: u32| (a >> sh & 0xff).abs_diff(b >> sh & 0xff);
+    d(16).max(d(8)).max(d(0))
+}
+
 /// WCAG contrast ratio between two colors (1.0 … 21.0).
 fn contrast(a: u32, b: u32) -> f32 {
     let (l1, l2) = (relative_luminance(a), relative_luminance(b));
@@ -223,6 +555,63 @@ fn is_dark(bg: u32) -> bool {
     relative_luminance(bg) < 0.5
 }
 
+/// Whether `a` is the lighter of two colors. Lets callers pick "the light end of
+/// this theme's axis" without caring which of background/foreground that is —
+/// e.g. a switch knob, which is near-white in both macOS appearances.
+pub(crate) fn is_lighter(a: u32, b: u32) -> bool {
+    relative_luminance(a) > relative_luminance(b)
+}
+
+/// The minimum contrast an accent must clear against the background before it is
+/// allowed to carry ink (a caret, a link, a focus ring). 3:1 is the WCAG
+/// large-text / non-text floor.
+const ACCENT_FLOOR: f32 = 3.0;
+
+/// The WCAG AA text floor. What a coloured *label* must clear on its ground.
+const TEXT_FLOOR: f32 = 4.5;
+
+/// Make a hued seed usable at `floor` against `bg`: keep it when it already
+/// clears, otherwise drive it *away from the background* — toward white on a dark
+/// theme, black on a light one — until it does.
+///
+/// This is why a seed colour can never be used raw. The bundled Light theme's
+/// accent `#00c2ff` manages 2.07:1 on white and the built-ins' accents span
+/// 2.07:1 to 8.43:1; the ANSI reds behind [`Semantics`] are just as uneven. Any
+/// unconditional use of one is a coin flip on some theme.
+///
+/// It drives toward black/white rather than toward the theme's foreground because
+/// the foreground is usually *tinted*, and blending into a tint destroys hue at
+/// exactly the moment hue matters most — when a seed is far from the floor and so
+/// has to travel far. On Rosé Pine Dawn, whose foreground is the purple-grey
+/// `#575279`, routing through it turned the ANSI red into `#9a5e7a` and the ANSI
+/// yellow into `#876a62`: two muddy mauves a user could not tell apart, which is
+/// no use at all for "did that fail or is it just a warning". Black and white are
+/// neutral, so the hue survives the trip.
+fn legible_ink(bg: u32, seed: u32, floor: f32) -> u32 {
+    if contrast(seed, bg) >= floor {
+        return seed;
+    }
+    // Whichever extreme the background is *further* from, exactly as
+    // [`legible_foreground`] picks it — not `is_dark`, whose 0.5 luminance
+    // threshold is the wrong question here. The two answers only diverge on a
+    // midtone background (luminance 0.18…0.5), where `is_dark` still says "dark"
+    // but black outreaches white: an imported scheme on a mid-grey ground would
+    // have been driven to pure white and clamped there *below* the floor, losing
+    // the hue and failing the job in one go. Every built-in is far enough from
+    // the midpoint that this picks what `is_dark` did.
+    let away = if contrast(0xffffff, bg) >= contrast(0x000000, bg) {
+        0xffffff
+    } else {
+        0x000000
+    };
+    bisect_contrast(seed, away, bg, floor)
+}
+
+/// The accent conditioned for ink (caret, focus ring, a switch's checked track).
+fn legible_accent(bg: u32, accent: u32) -> u32 {
+    legible_ink(bg, accent, ACCENT_FLOOR)
+}
+
 /// Guarantee a legible default text color: keep the authored `fg` if it clears
 /// the WCAG AA text threshold (4.5) against `bg`, otherwise fall back to pure
 /// black or white — whichever contrasts more. Protects hand-authored and
@@ -980,6 +1369,336 @@ mod tests {
         }
     }
 
+    /// Every surface's state ladder must be *strictly ordered and separable* on
+    /// every built-in — this is the regression guard for issue #197, where the
+    /// segmented control's selected fill sat 1.03:1 from its unselected siblings
+    /// on Dracula (and no better than 1.20:1 on any other bundled theme).
+    ///
+    /// The assertions are deliberately below the [`state`] targets: they pin the
+    /// *property* (a selection is distinguishable from resting and from hover on
+    /// every surface of every theme), not the current taste, so retuning the
+    /// constants doesn't force a test edit but abandoning the ladder does.
+    #[test]
+    fn state_ladder_is_separable_on_every_surface() {
+        for t in builtins() {
+            let s = t.surfaces();
+            for (name, sf) in [
+                ("window", s.window),
+                ("sidebar", s.sidebar),
+                ("popover", s.popover),
+            ] {
+                let sel_base = contrast(sf.selected, sf.base);
+                let sel_hover = contrast(sf.selected, sf.hover);
+                let hover_base = contrast(sf.hover, sf.base);
+                assert!(
+                    sel_base >= 1.6,
+                    "{}/{name}: selected is only {sel_base:.2}:1 from the surface",
+                    t.id
+                );
+                assert!(
+                    sel_hover >= 1.3,
+                    "{}/{name}: selected is only {sel_hover:.2}:1 from hover",
+                    t.id
+                );
+                assert!(
+                    hover_base >= 1.1,
+                    "{}/{name}: hover is only {hover_base:.2}:1 from the surface",
+                    t.id
+                );
+                assert!(
+                    contrast(sf.pressed, sf.base) > sel_base,
+                    "{}/{name}: pressed must read past selected",
+                    t.id
+                );
+            }
+        }
+    }
+
+    /// The whole point of a ratio target over a blend ratio: the *perceived* step
+    /// is the same on every theme. A fixed `mix` put selected-vs-resting between
+    /// 1.20:1 and 1.47:1 depending on the seed; these must all agree.
+    #[test]
+    fn state_ladder_is_theme_independent() {
+        let ratios: Vec<f32> = builtins()
+            .iter()
+            .map(|t| {
+                let w = t.surfaces().window;
+                contrast(w.selected, w.base)
+            })
+            .collect();
+        let (lo, hi) = ratios
+            .iter()
+            .fold((f32::MAX, 0.0f32), |(l, h), r| (l.min(*r), h.max(*r)));
+        assert!(
+            hi - lo < 0.05,
+            "selected step drifts across themes: {lo:.2}:1 … {hi:.2}:1"
+        );
+        assert!(
+            (lo - state::SELECTED).abs() < 0.05,
+            "selected step {lo:.2}:1 missed its {:.2}:1 target",
+            state::SELECTED
+        );
+    }
+
+    /// Anchoring `SELECTED` to 1.70 must leave the signed-off Dracula highlight
+    /// where it was — the value the palette/menu look was tuned against. This is
+    /// what makes the fix a no-op on the theme it was designed on and a lift for
+    /// everything else; if a retune moves Dracula, that was a taste decision and
+    /// wants to be a deliberate one.
+    #[test]
+    fn dracula_selection_matches_the_signed_off_grey() {
+        let dracula = builtins().into_iter().find(|t| t.id == "dracula").unwrap();
+        let bg = dracula.background_color();
+        let legacy = mix(bg, dracula.foreground, 0.17); // the old `list_active`
+        let now = dracula.surfaces().window.selected;
+        assert!(
+            contrast(now, legacy) < 1.05,
+            "Dracula's selection moved: {now:#08x} vs the tuned {legacy:#08x}"
+        );
+    }
+
+    /// A resting label must clear WCAG AA on the surface it sits on, for every
+    /// theme *and* every surface — a menu row's label sits on `popover`, not on
+    /// the window background, and the fixed dim it replaced was anchored to the
+    /// latter wherever it was used.
+    #[test]
+    fn resting_labels_stay_readable() {
+        for t in builtins() {
+            let s = t.surfaces();
+            for (name, sf) in [("window", s.window), ("popover", s.popover)] {
+                let ratio = contrast(sf.text_resting, sf.base);
+                assert!(
+                    ratio >= 4.5,
+                    "{}/{name}: resting label only {ratio:.2}:1",
+                    t.id
+                );
+            }
+        }
+    }
+
+    /// The text channel's two invariants, on every surface of every theme.
+    ///
+    /// 1. A selected label is readable **on its own fill** — never merely on the
+    ///    surface it would have sat on unselected. Getting this wrong is subtle:
+    ///    raising the fill toward the foreground eats the label's contrast, and
+    ///    Catppuccin Latte's selected label landed at 4.14:1 (below the 4.57:1 of
+    ///    the *resting* labels beside it) before `ink_on` existed.
+    /// 2. The two label colors differ enough to read as a step, so the channel
+    ///    still says something when the fill is washed out — a translucent
+    ///    window, a blurred background, an imported seed nobody vetted.
+    #[test]
+    fn label_channel_is_readable_and_stepped() {
+        for t in builtins() {
+            let s = t.surfaces();
+            for (name, sf) in [
+                ("window", s.window),
+                ("sidebar", s.sidebar),
+                ("popover", s.popover),
+            ] {
+                let on_fill = contrast(sf.text_selected, sf.selected);
+                assert!(
+                    on_fill >= 4.5,
+                    "{}/{name}: selected label only {on_fill:.2}:1 on its own fill",
+                    t.id
+                );
+                let step = contrast(sf.text_selected, sf.text_resting);
+                assert!(
+                    step >= 1.35,
+                    "{}/{name}: label step is only {step:.2}:1 — the channel says nothing",
+                    t.id
+                );
+            }
+        }
+    }
+
+    /// A switch's two tracks must both be distinguishable *from each other* and
+    /// from the surface, and the knob — one colour serving both states — has to
+    /// stay visible on each.
+    ///
+    /// The toggles shipped inverted on every dark theme (stock near-black knob on
+    /// a near-white checked track, and invisible on the unchecked one) because
+    /// `switch`, `switch_thumb` and `tokens.background` were all unset. This pins
+    /// the arrangement that replaced it: knob at the light end of the theme's
+    /// axis, unchecked track on the ladder, checked track on the accent.
+    ///
+    /// The knob-on-checked-track floor is 1.25, not 3 — a white knob on a
+    /// coloured track is separated by the component's `shadow_md`, exactly as it
+    /// is in macOS, and demanding raw contrast there would force every accent to
+    /// go dark.
+    #[test]
+    fn switch_tracks_and_knob_stay_legible() {
+        for t in builtins() {
+            let m = t.neutrals();
+            let unchecked = t.surfaces().window.selected;
+            let checked = m.accent;
+            let knob = if is_lighter(m.background, m.foreground) {
+                m.background
+            } else {
+                m.foreground
+            };
+            assert!(
+                contrast(knob, unchecked) >= 1.25,
+                "{}: knob {knob:#08x} lost on the unchecked track {unchecked:#08x}",
+                t.id
+            );
+            assert!(
+                contrast(knob, checked) >= 1.25,
+                "{}: knob {knob:#08x} lost on the checked track {checked:#08x}",
+                t.id
+            );
+            // The two states must not be near-identical greys, or the switch says
+            // nothing but the knob's position.
+            assert!(
+                contrast(checked, unchecked) >= 1.3,
+                "{}: checked and unchecked tracks are {:.2}:1 apart",
+                t.id,
+                contrast(checked, unchecked)
+            );
+        }
+    }
+
+    /// Status colours must clear their floors on every theme, and — the point of
+    /// deriving them from the theme's own ANSI-16 — must stay *recognisable* as
+    /// red / green / yellow rather than converging on the foreground.
+    ///
+    /// Before this, `danger` was gpui-component's stock `#f87171` on every theme:
+    /// 2.45:1 on Catppuccin Latte (under even the 3:1 non-text floor) and a
+    /// different red from the `#ff5555` the terminal beside it paints.
+    #[test]
+    fn semantic_colors_clear_their_floors() {
+        for t in builtins() {
+            let bg = t.background_color();
+            let s = t.semantics();
+            for (name, c) in [
+                ("danger", s.danger),
+                ("warning", s.warning),
+                ("success", s.success),
+                ("info", s.info),
+                ("link", s.link),
+            ] {
+                assert!(
+                    contrast(c.ink, bg) >= TEXT_FLOOR - 0.01,
+                    "{}/{name}: ink {:#08x} only {:.2}:1 on the background",
+                    t.id,
+                    c.ink,
+                    contrast(c.ink, bg)
+                );
+                assert!(
+                    contrast(c.fill, bg) >= ACCENT_FLOOR - 0.01,
+                    "{}/{name}: fill {:#08x} only {:.2}:1 on the background",
+                    t.id,
+                    c.fill,
+                    contrast(c.fill, bg)
+                );
+                assert!(
+                    contrast(c.on_fill, c.fill) >= TEXT_FLOOR - 0.01,
+                    "{}/{name}: text on its own fill is only {:.2}:1",
+                    t.id,
+                    contrast(c.on_fill, c.fill)
+                );
+            }
+            // Conditioning must not wash the hues into each other: a user has to
+            // be able to tell an error from a success without reading the label.
+            for (a, b, pair) in [
+                (s.danger.ink, s.success.ink, "danger/success"),
+                (s.danger.ink, s.warning.ink, "danger/warning"),
+                (s.success.ink, s.warning.ink, "success/warning"),
+            ] {
+                assert!(
+                    channel_distance(a, b) >= 40,
+                    "{}: {pair} collapsed to nearly the same colour ({a:#08x} vs {b:#08x})",
+                    t.id
+                );
+            }
+        }
+    }
+
+    /// Each status colour must stay recognisably its own theme's hue — that is
+    /// the whole reason for sourcing them from ANSI-16 rather than a brand set.
+    /// Where a seed already clears its floor it must pass through untouched.
+    #[test]
+    fn semantic_colors_keep_the_theme_hue() {
+        let dracula = builtins().into_iter().find(|t| t.id == "dracula").unwrap();
+        let ansi_red = {
+            let (r, g, b) = dracula.ansi16[1];
+            (r as u32) << 16 | (g as u32) << 8 | b as u32
+        };
+        assert_eq!(ansi_red, 0xff5555, "Dracula's ANSI red moved");
+        // 4.53:1 on Dracula's background — already over AA, so it is used as-is
+        // and the danger dot matches the terminal's own error output exactly.
+        assert_eq!(dracula.semantics().danger.ink, ansi_red);
+    }
+
+    /// Every theme's accent must be able to carry ink (caret, link, focus ring).
+    /// The bundled Light theme's raw `#00c2ff` manages 2.07:1 on white, which is
+    /// why this conditioning exists rather than using the seed directly.
+    #[test]
+    fn accents_are_conditioned_to_carry_ink() {
+        for t in builtins() {
+            let bg = t.background_color();
+            let a = t.neutrals().accent;
+            let ratio = contrast(a, bg);
+            assert!(
+                ratio >= ACCENT_FLOOR - 0.01,
+                "{}: accent {a:#08x} only {ratio:.2}:1 on the background",
+                t.id
+            );
+        }
+        // ...and a seed that already clears the floor is passed through untouched,
+        // so conditioning never dulls a theme that didn't need it.
+        let rose = builtins()
+            .into_iter()
+            .find(|t| t.id == "rose_pine")
+            .unwrap();
+        assert_eq!(rose.neutrals().accent, rose.accent);
+    }
+
+    /// `raise`/`dim` must land *just* past their targets from either direction,
+    /// and clamp rather than return a mid-range guess when one is unreachable.
+    ///
+    /// "Just past" is one 8-bit channel step, not zero: the tightest grey clearing
+    /// 2.0:1 on black is `#404040` at 2.025:1, because a channel step near there
+    /// moves the ratio by ~0.03. Anything tighter would be asserting sub-pixel
+    /// precision the framebuffer can't hold.
+    #[test]
+    fn contrast_bisection_hits_its_target() {
+        const SLACK: f32 = 0.05;
+        // Reachable, rising: a fill lifted off black.
+        let f = raise(0x000000, 0xffffff, 2.0);
+        assert!((2.0..2.0 + SLACK).contains(&contrast(f, 0x000000)));
+        // Reachable, rising: lifted off white — the direction flips, the API
+        // doesn't (this is what the old fixed-mix ladder got wrong per theme).
+        let f = raise(0xffffff, 0x000000, 2.0);
+        assert!((2.0..2.0 + SLACK).contains(&contrast(f, 0xffffff)));
+        // Reachable, falling: white ink dimmed to just above AA on black.
+        let d = dim(0xffffff, 0x000000, 4.5);
+        assert!((contrast(d, 0x000000) - 4.5).abs() < SLACK);
+        // Unreachable: nothing between these two clears 21:1, so clamp to the
+        // far endpoint instead of bisecting to something arbitrary.
+        assert_eq!(raise(0x000000, 0x808080, 21.0), 0x808080);
+    }
+
+    /// Conditioning has to take the extreme it can actually *reach*, which on a
+    /// midtone ground is not the one `is_dark`'s 0.5 luminance threshold names.
+    /// A mid-grey background is "dark" by that test, yet white tops out at
+    /// 3.95:1 on it while black manages 5.32:1 — so driving toward white would
+    /// clamp at pure white, below the floor and with the hue thrown away, in the
+    /// one case where a status colour most needs both. Reachable only for an
+    /// imported scheme; every built-in sits far enough from the midpoint that
+    /// this picks the same extreme `is_dark` did.
+    #[test]
+    fn semantic_conditioning_survives_a_midtone_background() {
+        let bg = 0x808080;
+        for seed in [0xff5555u32, 0x50fa7b, 0xf1fa8c, 0x8be9fd] {
+            let ink = legible_ink(bg, seed, TEXT_FLOOR);
+            assert!(
+                contrast(ink, bg) >= TEXT_FLOOR - 0.01,
+                "{seed:#08x} conditioned to {ink:#08x}, only {:.2}:1 on a midtone ground",
+                contrast(ink, bg)
+            );
+        }
+    }
+
     /// A bad foreground is swapped for a legible black/white; a good one is kept.
     #[test]
     fn legible_foreground_rescues_unreadable_text() {

src/ui/right_panel.rs

@@ -962,6 +962,9 @@ impl Tty7App {
     /// Newest first because that's the end you came from: you scrolled past the
     /// thing you want, and the list should start where your attention is.
     fn render_panel_outline(&mut self, window: &mut Window, cx: &mut Context<Self>) -> AnyElement {
+        // This panel is a sunk rail (see the `sidebar` fill on its container), so
+        // its rows read the sidebar ladder.
+        let sf = cx.global::<crate::ui::presets::Surfaces>().sidebar;
         let Some(leaf) = self
             .tabs
             .get(self.active)
@@ -1027,7 +1030,7 @@ impl Tty7App {
                     .py(px(3.))
                     .rounded(px(5.))
                     .cursor_pointer()
-                    .hover(|s| s.bg(cx.theme().sidebar_accent.opacity(0.55)))
+                    .hover(|s| s.bg(gpui::rgb(sf.hover)))
                     .on_click(cx.listener(move |_this, _, _window, cx| {
                         leaf.update(cx, |view, cx| {
                             view.scroll_to_mark(row, cx);
@@ -1074,6 +1077,7 @@ impl Tty7App {
     /// diff overlay's hunk cards, which need far more than 260px to be readable.
     /// Clicking a row opens the full overlay on that repo.
     fn render_panel_changes(&mut self, window: &mut Window, cx: &mut Context<Self>) -> AnyElement {
+        let sf = cx.global::<crate::ui::presets::Surfaces>().sidebar;
         let cwd = self
             .tabs
             .get(self.active)
@@ -1160,8 +1164,13 @@ impl Tty7App {
                             .py(px(3.))
                             .rounded(px(5.))
                             .cursor_pointer()
-                            .hover(|s| s.bg(cx.theme().sidebar_accent.opacity(0.55)))
-                            .when(selected, |s| s.bg(cx.theme().sidebar_accent))
+                            // The rail's own ladder. Hover used to be this fill at
+                            // 55% alpha, which on a light theme is a tint nobody
+                            // can see — the same mistake `chrome_tile_variant_for`
+                            // already documents having fixed in the title bar, made
+                            // again here because there was nothing to reuse.
+                            .hover(|s| s.bg(gpui::rgb(sf.hover)))
+                            .when(selected, |s| s.bg(gpui::rgb(sf.selected)))
                             .on_click({
                                 let cwd = cwd.clone();
                                 let path = path.clone();

src/ui/settings.rs

@@ -11,8 +11,7 @@ use gpui::{
     prelude::*, px, relative, rgb,
 };
 use gpui_component::InteractiveElementExt as _;
-use gpui_component::Selectable as _;
-use gpui_component::button::{Button, ButtonGroup, ButtonVariants as _};
+use gpui_component::button::{Button, ButtonVariants as _};
 use gpui_component::color_picker::{ColorPicker, ColorPickerState};
 use gpui_component::input::{Input, InputEvent, InputState};
 use gpui_component::link::Link;
@@ -20,7 +19,6 @@ use gpui_component::menu::{ContextMenuExt as _, DropdownMenu as _, PopupMenu, Po
 use gpui_component::select::{SearchableVec, Select, SelectState};
 use gpui_component::sidebar::{Sidebar, SidebarCollapsible, SidebarMenu, SidebarMenuItem};
 use gpui_component::slider::{Slider, SliderState};
-use gpui_component::switch::Switch;
 use gpui_component::{
     ActiveTheme as _, Icon, IconName, Sizable as _, WindowExt as _, h_flex, v_flex,
 };
@@ -1147,7 +1145,7 @@ impl Tty7App {
             .px_2p5()
             .mx_neg_2p5()
             .rounded_lg()
-            .hover(|h| h.bg(theme.secondary.opacity(0.2)))
+            .hover(|h| h.bg(gpui::rgb(cx.global::<presets::Surfaces>().window.hover)))
             .child(
                 v_flex()
                     .gap_0p5()
@@ -1173,13 +1171,30 @@ impl Tty7App {
             .child(h_flex().flex_shrink_0().child(control))
     }
 
-    /// A segmented control (gpui-component's `ButtonGroup`, outline) for a small
-    /// set of mutually-exclusive options — the refined stand-in for a raw row of
-    /// radio circles, which read as an unstyled form beside the sheet's tuned
-    /// steppers and chips. Joined outline segments with a soft-filled active one
-    /// speak the same segmented language as the −│value│+ stepper; `small` pins
-    /// every option control to the same 24px height as the selects beside them.
-    /// `selected` is the active index; `on_pick` fires with the newly chosen one.
+    /// A segmented control for a small set of mutually-exclusive options — the
+    /// refined stand-in for a raw row of radio circles, which read as an unstyled
+    /// form beside the sheet's tuned steppers and chips. Joined segments in a
+    /// single outlined track, one of them filled, speak the same segmented
+    /// language as the −│value│+ stepper right beside them; the 24px height
+    /// matches the selects in the same rows. `selected` is the active index;
+    /// `on_pick` fires with the newly chosen one.
+    ///
+    /// # Why this is hand-rolled
+    ///
+    /// It used to be gpui-component's `ButtonGroup::outline()` with
+    /// `Button::selected`, and that is what issue #197 was reported against. That
+    /// path derives the selected segment's fill from `Theme::input` and gives it
+    /// the *same* border and the *same* label color as its unselected siblings —
+    /// so the entire selection signal was one fill, and that fill came from a
+    /// grey unrelated to the active theme. On Dracula it measured **1.03:1**.
+    ///
+    /// `Theme::input` is now themed (see `ui::theme::apply_theme`), which fixes
+    /// the stock control for inputs and selects. But a segmented control is the
+    /// one place in the app where several options sit visibly side by side with a
+    /// *static* selection, so it is precisely where a fill alone is not enough
+    /// (see `presets::Surface`) — and the stock button exposes no way to vary the
+    /// label's weight. Owning the 30 lines is cheaper than a fork patch, and it
+    /// puts the control on the same ladder every hand-rolled surface reads.
     pub(crate) fn segmented(
         &self,
         id: &'static str,
@@ -1188,19 +1203,78 @@ impl Tty7App {
         cx: &mut Context<Self>,
         on_pick: impl Fn(&mut Self, usize, &mut Window, &mut Context<Self>) + 'static,
     ) -> AnyElement {
-        ButtonGroup::new(id)
-            .outline()
-            .small()
+        let sf = cx.global::<presets::Surfaces>().window;
+        self.segmented_on(sf, id, options, selected, cx, on_pick)
+    }
+
+    /// [`Self::segmented`] for a control that does *not* sit on the settings
+    /// sheet. The track paints its own opaque ground, so it has to be told which
+    /// one: dropped on the right panel's sunk rail, a window-surface track reads
+    /// as a faintly darker box cut out of the column it sits in — and every rung
+    /// above it was derived against the wrong ground.
+    pub(crate) fn segmented_on(
+        &self,
+        sf: presets::Surface,
+        id: &'static str,
+        options: &'static [&'static str],
+        selected: usize,
+        cx: &mut Context<Self>,
+        on_pick: impl Fn(&mut Self, usize, &mut Window, &mut Context<Self>) + 'static,
+    ) -> AnyElement {
+        let border = cx.theme().border;
+        let on_pick = std::rc::Rc::new(on_pick);
+        h_flex()
+            .id(id)
+            .h(px(24.))
+            .rounded_lg()
+            .border_1()
+            .border_color(border)
+            // The track paints its own ground rather than letting the sheet show
+            // through. Every rung of the ladder was derived against this colour,
+            // so painting it is what makes those ratios true — a control that
+            // leaves its ground to whatever it happens to be composited over is
+            // the shape of the bug this whole change is about.
+            .bg(gpui::rgb(sf.base))
+            // One track, clipped so the end segments' fills follow its rounding
+            // instead of squaring off the corners they sit in.
+            .overflow_hidden()
             .children(options.iter().enumerate().map(|(i, label)| {
-                // `(id, i)` keeps each segment's element id unique across the
-                // several segmented controls on the page.
-                Button::new((id, i)).label(*label).selected(i == selected)
-            }))
-            .on_click(cx.listener(move |this, clicks: &Vec<usize>, window, cx| {
-                // Single-select: `clicks` carries just the newly chosen index.
-                if let Some(&ix) = clicks.first() {
-                    on_pick(this, ix, window, cx);
-                }
+                let active = i == selected;
+                let on_pick = on_pick.clone();
+                h_flex()
+                    // `(id, i)` keeps each segment's element id unique across the
+                    // several segmented controls on the page.
+                    .id((id, i))
+                    .items_center()
+                    .justify_center()
+                    .h_full()
+                    .px_2p5()
+                    .text_sm()
+                    .cursor_pointer()
+                    // Hairlines *between* segments only — the track already owns
+                    // its outer edge, and a border on the first segment would
+                    // double it.
+                    .when(i > 0, |s| s.border_l_1().border_color(border))
+                    // Both channels, every time. The fill locates the selection in
+                    // the row; the label color and weight say it is the one — and
+                    // keep saying it on a translucent window, where the fill is
+                    // washing over whatever is behind the sheet.
+                    .when(active, |s| {
+                        s.bg(gpui::rgb(sf.selected))
+                            .text_color(gpui::rgb(sf.text_selected))
+                            .font_weight(FontWeight::MEDIUM)
+                    })
+                    .when(!active, |s| {
+                        s.text_color(gpui::rgb(sf.text_resting))
+                            .hover(|h| h.bg(gpui::rgb(sf.hover)))
+                    })
+                    // Pressed reads past selected, so pushing the segment that is
+                    // already chosen still acknowledges the click.
+                    .active(|s| s.bg(gpui::rgb(sf.pressed)))
+                    .child(*label)
+                    .on_click(cx.listener(move |this, _, window, cx| {
+                        on_pick(this, i, window, cx);
+                    }))
             }))
             .into_any_element()
     }
@@ -1210,7 +1284,10 @@ impl Tty7App {
         let theme = cx.theme();
         let foreground = theme.foreground;
         let border = theme.border;
-        let hover_bg = theme.secondary.opacity(0.6);
+        // Hover comes off the ladder; `stepper_bg` stays a soft resting tint —
+        // it decorates a container rather than signalling a state, which is the
+        // one job an alpha-multiplied grey is still fine for.
+        let hover_bg = gpui::rgb(cx.global::<presets::Surfaces>().window.hover);
         let stepper_bg = theme.secondary.opacity(0.35);
         let font_size = self.font_size;
         let (font_select, font_bold_select, font_italic_select) = match self.active_settings() {
@@ -1334,7 +1411,7 @@ impl Tty7App {
         let font_family_control = font_dropdown(&font_select);
         let font_bold_control = font_dropdown(&font_bold_select);
         let font_italic_control = font_dropdown(&font_italic_select);
-        let ligature_switch = Switch::new("font-ligatures")
+        let ligature_switch = crate::ui::theme::switch("font-ligatures", cx)
             .checked(font_ligatures)
             .on_click(cx.listener(|this, on: &bool, _w, cx| this.set_font_ligatures(*on, cx)))
             .into_any_element();
@@ -1360,7 +1437,7 @@ impl Tty7App {
         );
         // Blink lives here beside the shape — one Cursor home, not "shape is
         // appearance, blink is behavior" split across two pages.
-        let blink_switch = Switch::new("cursor-blink")
+        let blink_switch = crate::ui::theme::switch("cursor-blink", cx)
             .checked(cursor_blink)
             .on_click(cx.listener(|this, on: &bool, _w, cx| this.set_cursor_blink(*on, cx)))
             .into_any_element();
@@ -1463,7 +1540,7 @@ impl Tty7App {
                     .child(format!("{:.0}%", opacity * 100.)),
             )
             .into_any_element();
-        let blur_switch = Switch::new("window-blur")
+        let blur_switch = crate::ui::theme::switch("window-blur", cx)
             .checked(blur)
             .on_click(
                 cx.listener(|this, on: &bool, window, cx| this.set_window_blur(*on, window, cx)),
@@ -1723,6 +1800,8 @@ impl Tty7App {
     /// saved-profile list (each row selects into the detail pane).
     fn render_ssh_master(&self, cx: &mut Context<Self>) -> AnyElement {
         let muted = cx.theme().muted_foreground;
+        // Rows in this list paint on the settings sheet, i.e. the window surface.
+        let sf = cx.global::<presets::Surfaces>().window;
         let profiles = cx.global::<Config>().ssh_profiles.clone();
         let detail = self
             .active_settings()
@@ -1790,12 +1869,18 @@ impl Tty7App {
                     .py_2()
                     .px_2()
                     .rounded_md()
-                    .when(selected, |r| r.bg(cx.theme().secondary.opacity(0.4)))
+                    // The window ladder, both channels. This row used to tint with
+                    // `secondary.opacity(0.4)` — a 9% grey at 40% alpha, i.e. an
+                    // effective 3.6% tint, which put the selected row 1.05–1.12:1
+                    // from a resting one and 1.02–1.06:1 from a hovered one. It was
+                    // the second site named in issue #197. Multiplying a soft grey
+                    // by alpha is how a fill silently disappears: the result depends
+                    // on whatever it happens to be composited over, which is
+                    // exactly the unknown a per-surface ladder removes.
+                    .when(selected, |r| r.bg(gpui::rgb(sf.selected)))
                     // A subtle hover fill so the whole row reads as the (clickable)
                     // select affordance; the selected row keeps its own highlight.
-                    .when(!selected, |r| {
-                        r.hover(|s| s.bg(cx.theme().secondary.opacity(0.2)))
-                    })
+                    .when(!selected, |r| r.hover(|s| s.bg(gpui::rgb(sf.hover))))
                     // Left-click anywhere on the row selects it — its edit form
                     // opens in the detail pane. Clicks on the trailing ⋯ are
                     // swallowed by its wrapper, so they don't also start an edit.
@@ -1818,7 +1903,21 @@ impl Tty7App {
                         v_flex()
                             .min_w_0()
                             .gap_0p5()
-                            .child(div().text_sm().truncate().child(title))
+                            .child(
+                                div()
+                                    .text_sm()
+                                    .truncate()
+                                    // The label channel: the selected row's title
+                                    // steps up in colour and weight, so which
+                                    // profile is loaded in the detail pane reads
+                                    // from the type and not from the fill alone.
+                                    .when(selected, |d| {
+                                        d.text_color(gpui::rgb(sf.text_selected))
+                                            .font_weight(FontWeight::MEDIUM)
+                                    })
+                                    .when(!selected, |d| d.text_color(gpui::rgb(sf.text_resting)))
+                                    .child(title),
+                            )
                             .child(div().text_xs().text_color(muted).truncate().child(subtitle)),
                     )
                     .child(
@@ -1964,13 +2063,13 @@ impl Tty7App {
     /// under the form or the empty-state hint.
     fn render_ssh_security_block(&self, cx: &mut Context<Self>) -> AnyElement {
         let verify = cx.global::<Config>().verify_host_keys;
-        let verify_switch = Switch::new("ssh-verify-host-keys")
+        let verify_switch = crate::ui::theme::switch("ssh-verify-host-keys", cx)
             .checked(verify)
             .on_click(cx.listener(|this, on: &bool, _w, cx| this.set_verify_host_keys(*on, cx)))
             .into_any_element();
 
         let warn_on_close = cx.global::<Config>().ssh_warn_on_close;
-        let warn_switch = Switch::new("ssh-warn-on-close")
+        let warn_switch = crate::ui::theme::switch("ssh-warn-on-close", cx)
             .checked(warn_on_close)
             .on_click(cx.listener(|this, on: &bool, _w, cx| this.set_ssh_warn_on_close(*on, cx)))
             .into_any_element();
@@ -2639,7 +2738,7 @@ impl Tty7App {
                 self.settings_row(
                     "Agent forwarding",
                     "Forward the local ssh-agent to the session.",
-                    Switch::new("ssh-form-agent")
+                    crate::ui::theme::switch("ssh-form-agent", cx)
                         .checked(form.agent_forward)
                         .on_click(cx.listener(|this, on: &bool, _w, cx| {
                             if let Some(f) = this.ssh_form_mut() {
@@ -2732,7 +2831,7 @@ impl Tty7App {
                 self.settings_row(
                     "X11 forwarding",
                     "Request X11 forwarding (needs XQuartz on macOS).",
-                    Switch::new("ssh-form-x11")
+                    crate::ui::theme::switch("ssh-form-x11", cx)
                         .checked(form.x11)
                         .on_click(cx.listener(|this, on: &bool, _w, cx| {
                             if let Some(f) = this.ssh_form_mut() {
@@ -2748,7 +2847,7 @@ impl Tty7App {
                 self.settings_row(
                     "Shell integration",
                     "Let the remote shell report prompts, exit codes and directory.",
-                    Switch::new("ssh-form-shell-integration")
+                    crate::ui::theme::switch("ssh-form-shell-integration", cx)
                         .checked(form.shell_integration)
                         .on_click(cx.listener(|this, on: &bool, _w, cx| {
                             if let Some(f) = this.ssh_form_mut() {
@@ -2771,7 +2870,7 @@ impl Tty7App {
                 self.settings_row(
                     "Skip banner",
                     "Suppress the server login banner.",
-                    Switch::new("ssh-form-banner")
+                    crate::ui::theme::switch("ssh-form-banner", cx)
                         .checked(form.skip_banner)
                         .on_click(cx.listener(|this, on: &bool, _w, cx| {
                             if let Some(f) = this.ssh_form_mut() {
@@ -2978,11 +3077,11 @@ impl Tty7App {
             None => return div().into_any_element(),
         };
 
-        let link_switch = Switch::new("term-link-url")
+        let link_switch = crate::ui::theme::switch("term-link-url", cx)
             .checked(link_url)
             .on_click(cx.listener(|this, on: &bool, _w, cx| this.set_link_url(*on, cx)))
             .into_any_element();
-        let ssh_loopback_switch = Switch::new("term-ssh-loopback-forward")
+        let ssh_loopback_switch = crate::ui::theme::switch("term-ssh-loopback-forward", cx)
             .checked(ssh_loopback_forward)
             .on_click(cx.listener(|this, on: &bool, _w, cx| this.set_ssh_loopback_forward(*on, cx)))
             .into_any_element();
@@ -3005,17 +3104,17 @@ impl Tty7App {
             },
         );
 
-        let focus_switch = Switch::new("term-focus-follows")
+        let focus_switch = crate::ui::theme::switch("term-focus-follows", cx)
             .checked(focus_follows)
             .on_click(cx.listener(|this, on: &bool, _w, cx| this.set_focus_follows_mouse(*on, cx)))
             .into_any_element();
-        let mouse_hide_switch = Switch::new("term-mouse-hide")
+        let mouse_hide_switch = crate::ui::theme::switch("term-mouse-hide", cx)
             .checked(mouse_hide)
             .on_click(
                 cx.listener(|this, on: &bool, _w, cx| this.set_mouse_hide_while_typing(*on, cx)),
             )
             .into_any_element();
-        let mouse_report_switch = Switch::new("term-mouse-report")
+        let mouse_report_switch = crate::ui::theme::switch("term-mouse-report", cx)
             .checked(mouse_reporting)
             .on_click(cx.listener(|this, on: &bool, _w, cx| this.set_mouse_reporting(*on, cx)))
             .into_any_element();
@@ -3143,30 +3242,30 @@ impl Tty7App {
         let copy_on_select = cfg.copy_on_select;
         let clip_trim = cfg.clipboard_trim_trailing_spaces;
 
-        let tab_completion_switch = Switch::new("term-tab-completion")
+        let tab_completion_switch = crate::ui::theme::switch("term-tab-completion", cx)
             .checked(tab_completion)
             .on_click(cx.listener(|this, on: &bool, _w, cx| this.set_tab_completion(*on, cx)))
             .into_any_element();
-        let history_search_switch = Switch::new("term-history-search")
+        let history_search_switch = crate::ui::theme::switch("term-history-search", cx)
             .checked(history_search)
             .on_click(cx.listener(|this, on: &bool, _w, cx| this.set_history_search(*on, cx)))
             .into_any_element();
-        let smart_select_switch = Switch::new("term-smart-select")
+        let smart_select_switch = crate::ui::theme::switch("term-smart-select", cx)
             .checked(smart_select)
             .on_click(cx.listener(|this, on: &bool, _w, cx| this.set_smart_select(*on, cx)))
             .into_any_element();
-        let copy_on_select_switch = Switch::new("term-copy-on-select")
+        let copy_on_select_switch = crate::ui::theme::switch("term-copy-on-select", cx)
             .checked(copy_on_select)
             .on_click(cx.listener(|this, on: &bool, _w, cx| this.set_copy_on_select(*on, cx)))
             .into_any_element();
-        let trim_switch = Switch::new("term-clip-trim")
+        let trim_switch = crate::ui::theme::switch("term-clip-trim", cx)
             .checked(clip_trim)
             .on_click(cx.listener(|this, on: &bool, _w, cx| this.set_clipboard_trim(*on, cx)))
             .into_any_element();
         // macOS only: the Option/special-character split this toggle resolves
         // doesn't exist on other platforms, where Alt always carries Meta.
         let option_alt_row = cfg!(target_os = "macos").then(|| {
-            let switch = Switch::new("term-option-as-alt")
+            let switch = crate::ui::theme::switch("term-option-as-alt", cx)
                 .checked(option_as_alt)
                 .on_click(
                     cx.listener(|this, on: &bool, _w, cx| this.set_macos_option_as_alt(*on, cx)),
@@ -3398,15 +3497,15 @@ impl Tty7App {
             },
         );
 
-        let restore_switch = Switch::new("wt-restore-session")
+        let restore_switch = crate::ui::theme::switch("wt-restore-session", cx)
             .checked(restore_session)
             .on_click(cx.listener(|this, on: &bool, _w, cx| this.set_restore_session(*on, cx)))
             .into_any_element();
-        let remember_window_switch = Switch::new("wt-remember-window")
+        let remember_window_switch = crate::ui::theme::switch("wt-remember-window", cx)
             .checked(remember_window_size)
             .on_click(cx.listener(|this, on: &bool, _w, cx| this.set_remember_window_size(*on, cx)))
             .into_any_element();
-        let tray_switch = Switch::new("wt-tray-icon")
+        let tray_switch = crate::ui::theme::switch("wt-tray-icon", cx)
             .checked(show_tray_icon)
             .on_click(cx.listener(|this, on: &bool, _w, cx| this.set_show_tray_icon(*on, cx)))
             .into_any_element();
@@ -3597,7 +3696,7 @@ impl Tty7App {
     /// the OS — one card per light/dark slot.
     fn render_theme_selection(&self, cx: &mut Context<Self>) -> AnyElement {
         let follow = cx.global::<Config>().theme_follow_system;
-        let follow_switch = Switch::new("theme-follow-system")
+        let follow_switch = crate::ui::theme::switch("theme-follow-system", cx)
             .checked(follow)
             .on_click(cx.listener(|this, on: &bool, window, cx| {
                 this.set_theme_follow_system(*on, window, cx)
@@ -3629,7 +3728,7 @@ impl Tty7App {
         let border = theme.border;
         let foreground = theme.foreground;
         let muted_fg = theme.muted_foreground;
-        let hover_bg = theme.secondary.opacity(0.5);
+        let hover_bg = gpui::rgb(cx.global::<presets::Surfaces>().window.hover);
         let surface = theme.secondary.opacity(0.28);
 
         let config = cx.global::<Config>();
@@ -3968,20 +4067,30 @@ impl Tty7App {
                 .child(tok)
         };
 
-        // A preset toggle button, highlighted when active.
-        let preset_button =
-            |id: &'static str, label: &'static str, value: &'static str, on: bool| {
-                Button::new(id).label(label).small().selected(on).on_click(
-                    cx.listener(move |this, _, _w, cx| this.set_keybinding_preset(value, cx)),
-                )
-            };
-        // A prefix choice button (tmux preset only).
-        let prefix_button =
-            |id: &'static str, label: &'static str, value: &'static str, on: bool| {
-                Button::new(id).label(label).small().selected(on).on_click(
-                    cx.listener(move |this, _, _w, cx| this.set_keybinding_prefix(value, cx)),
-                )
-            };
+        // Preset and prefix are each a one-of-two choice among visible siblings —
+        // a segmented control, and now built as one. They used to be loose
+        // `Button::selected` pairs, which put them on gpui-component's
+        // `tokens.button_active`: another field nothing set, so the "on" button
+        // wore a stock grey with no relation to the theme (issue #197's failure
+        // mode, in a different corner of the same page).
+        let preset_control = self.segmented(
+            "kb-preset",
+            &["Default", "tmux"],
+            usize::from(tmux),
+            cx,
+            |this, ix, _w, cx| {
+                this.set_keybinding_preset(if ix == 0 { "default" } else { "tmux" }, cx)
+            },
+        );
+        let prefix_control = self.segmented(
+            "kb-prefix",
+            &["Ctrl-B", "Ctrl-A"],
+            usize::from(prefix == "ctrl-a"),
+            cx,
+            |this, ix, _w, cx| {
+                this.set_keybinding_prefix(if ix == 0 { "ctrl-b" } else { "ctrl-a" }, cx)
+            },
+        );
 
         let preset_row = h_flex()
             .items_center()
@@ -4001,12 +4110,7 @@ impl Tty7App {
                         "tmux remaps pane/tab actions onto prefix sequences (e.g. Ctrl-B then C).",
                     )),
             )
-            .child(
-                h_flex()
-                    .gap_1()
-                    .child(preset_button("preset-default", "Default", "default", !tmux))
-                    .child(preset_button("preset-tmux", "tmux", "tmux", tmux)),
-            );
+            .child(h_flex().flex_shrink_0().child(preset_control));
 
         let prefix_row = h_flex()
             .items_center()
@@ -4019,22 +4123,7 @@ impl Tty7App {
                     .text_color(foreground)
                     .child("Prefix"),
             )
-            .child(
-                h_flex()
-                    .gap_1()
-                    .child(prefix_button(
-                        "prefix-ctrl-b",
-                        "Ctrl-B",
-                        "ctrl-b",
-                        prefix == "ctrl-b",
-                    ))
-                    .child(prefix_button(
-                        "prefix-ctrl-a",
-                        "Ctrl-A",
-                        "ctrl-a",
-                        prefix == "ctrl-a",
-                    )),
-            );
+            .child(h_flex().flex_shrink_0().child(prefix_control));
 
         let count = effective.len();
         let mut list = v_flex().mt_2();
@@ -4344,7 +4433,7 @@ impl Tty7App {
                             .gap_2()
                             .items_center()
                             .child(
-                                Switch::new("check-updates")
+                                crate::ui::theme::switch("check-updates", cx)
                                     .checked(check_for_updates)
                                     .on_click(cx.listener(|this, on: &bool, _w, cx| {
                                         this.set_check_for_updates(*on, cx)

src/ui/sftp.rs

@@ -1262,6 +1262,8 @@ impl Tty7App {
     /// "the parent folder" and matches the rows below rather than a toolbar action.
     fn render_sftp_go_up_row(&self, cx: &mut Context<Self>) -> AnyElement {
         let foreground = cx.theme().foreground;
+        // Matches the directory rows below it, which paint on the popover surface.
+        let sf = cx.global::<crate::ui::presets::Surfaces>().popover;
         h_flex()
             .id("sftp-go-up")
             .items_center()
@@ -1271,7 +1273,7 @@ impl Tty7App {
             .py_1()
             .rounded(cx.theme().radius)
             .cursor_pointer()
-            .hover(|s| s.bg(cx.theme().accent.opacity(0.5)))
+            .hover(|s| s.bg(gpui::rgb(sf.hover)))
             .child(
                 Icon::new(IconName::FolderOpen)
                     .xsmall()
@@ -1481,7 +1483,7 @@ impl Tty7App {
         let accent = cx.theme().accent;
         let border = cx.theme().border;
         let sidebar = cx.theme().sidebar;
-        let hover = cx.theme().sidebar_accent.opacity(0.4);
+        let hover = gpui::rgb(cx.global::<crate::ui::presets::Surfaces>().sidebar.hover);
         let expanded = self.sftp_panel.tray_expanded || history;
 
         // The summary line: how many are moving and how far along the run is, as

src/ui/tab_sidebar.rs

@@ -13,16 +13,13 @@
 
 use gpui::{
     Animation, AnimationExt as _, AnyElement, Axis, Bounds, Context, Div, FontWeight, MouseButton,
-    MouseDownEvent, MouseMoveEvent, MouseUpEvent, Pixels, SharedString, Stateful, Window,
-    WindowControlArea, canvas, deferred, div, ease_out_quint, linear_color_stop, linear_gradient,
-    prelude::*, px,
+    MouseDownEvent, MouseMoveEvent, MouseUpEvent, Pixels, SharedString, Stateful, Window, canvas,
+    deferred, div, ease_out_quint, linear_color_stop, linear_gradient, prelude::*, px,
 };
 use gpui_component::button::{Button, ButtonVariants as _};
 use gpui_component::input::Input;
 use gpui_component::menu::{ContextMenu, ContextMenuExt as _};
-use gpui_component::{
-    ActiveTheme as _, Icon, IconName, InteractiveElementExt as _, Sizable as _, h_flex, v_flex,
-};
+use gpui_component::{ActiveTheme as _, Icon, IconName, Sizable as _, h_flex, v_flex};
 use std::cell::{Cell, RefCell};
 use std::rc::Rc;
 
@@ -77,6 +74,8 @@ impl Tty7App {
         cx: &mut Context<Self>,
     ) -> impl IntoElement + use<> {
         let active = self.active;
+        // The rail is a sunk column, so its rows read the sidebar ladder.
+        let sf = cx.global::<crate::ui::presets::Surfaces>().sidebar;
         // While the bare ⌘/Ctrl hold is armed (see `ui::hints`), each of the
         // first nine rows swaps its close affordance for a ⌘N badge — same slot
         // and footprint as the chips, so the vertical list gets the identical
@@ -409,7 +408,7 @@ impl Tty7App {
                     })
                     .when(!is_active, |s| {
                         s.text_color(cx.theme().sidebar_foreground)
-                            .hover(|s| s.bg(cx.theme().sidebar_accent.opacity(0.5)))
+                            .hover(|s| s.bg(gpui::rgb(sf.hover)))
                     })
                     // Held: a light dimming so the row under your cursor reads
                     // as picked up. Not a lift — it stays in the rail's plane.
@@ -489,12 +488,13 @@ impl Tty7App {
                         // carries alpha; the inactive hover is a half-strength
                         // wash), so flatten them against `sidebar` to get the
                         // opaque colour the float must match.
-                        let backing = if is_active {
-                            cx.theme().sidebar.blend(cx.theme().sidebar_accent)
+                        // Both rungs are opaque ladder colours, so the float's
+                        // backing is just the rung itself — no flattening needed,
+                        // and no alpha to drift out of step with the row it copies.
+                        let backing: gpui::Hsla = if is_active {
+                            gpui::rgb(sf.selected).into()
                         } else {
-                            cx.theme()
-                                .sidebar
-                                .blend(cx.theme().sidebar_accent.opacity(0.5))
+                            gpui::rgb(sf.hover).into()
                         };
                         let mut fade_from = backing;
                         fade_from.a = 0.;
@@ -751,11 +751,35 @@ impl Tty7App {
         let controls = h_flex()
             .flex_shrink_0()
             .h(px(TITLE_BAR_HEIGHT))
+            // Same box as the real title bar this row stands in for, hairline
+            // included: gpui-component's `TitleBar` draws a `border_b_1` inside its
+            // own `TITLE_BAR_HEIGHT` (tty7 paints it transparent, but it still takes
+            // its pixel), so the bar centres its contents on 19.5 while an
+            // unbordered 40px row centres them on 20. Half a pixel is invisible on
+            // the line-art tiles, and *not* on the solid brand mark: collapsing the
+            // rail hands the mark from this row to the bar, and it visibly hopped up
+            // as it went. Reserve the same pixel here and the handover is still.
+            .border_b_1()
+            .border_color(cx.theme().transparent)
             .items_center()
             .justify_end()
             .gap(px(2.))
             // Glyph's ink, not hit box, on the content edge — see `TILE_PAD`.
             .pr(px(crate::ui::app::tile_trailing_inset()))
+            // The brand mark leads the row, on the rail's own content inset — the
+            // line the search magnifier and every row label below it start on, so
+            // it reads as the head of this column rather than a floating badge.
+            // The spacer is what keeps the controls pinned right once the row has
+            // a leading child (`justify_end` alone no longer does it).
+            .when_some(crate::ui::app::window_mark(), |row, mark| {
+                row.child(
+                    div()
+                        .flex_shrink_0()
+                        .pl(px(crate::ui::app::CONTENT_INSET))
+                        .child(mark),
+                )
+                .child(div().flex_1())
+            })
             // Both tiles are wrapped in an `occlude()` div, exactly like the
             // title-strip chrome. This row is a `WindowControlArea::Drag` (set
             // below), which on Windows maps to HTCAPTION — the OS claims the click
@@ -934,34 +958,13 @@ impl Tty7App {
                     //
                     // The real `TitleBar` — which carries the window's drag region
                     // — only spans the *right* column in this layout, so this strip
-                    // would be dead space you can't grab the window by. Make the
-                    // controls' own row act like the title bar it sits level with:
-                    // drag to move, double-click to zoom. Driven exactly like
-                    // `TitleBar` does it (and the settings overlay's stand-in
-                    // strip): a press arms a flag and the first *move* starts the
-                    // window move, so a plain click — and a double-click — still
-                    // lands intact, while the buttons on the right keep taking
-                    // their own clicks.
-                    .child({
-                        let should_move = Rc::new(Cell::new(false));
-                        controls
-                            .id("sidebar-titlebar-drag")
-                            .window_control_area(WindowControlArea::Drag)
-                            .on_mouse_down(MouseButton::Left, {
-                                let should_move = should_move.clone();
-                                move |_, _, _| should_move.set(true)
-                            })
-                            .on_mouse_up(MouseButton::Left, {
-                                let should_move = should_move.clone();
-                                move |_, _, _| should_move.set(false)
-                            })
-                            .on_mouse_move(move |_, window, _| {
-                                if should_move.replace(false) {
-                                    window.start_window_move();
-                                }
-                            })
-                            .on_double_click(|_, window, _| window.titlebar_double_click())
-                    })
+                    // would be dead space you can't grab the window by. `title_bar_drag`
+                    // makes the controls' row act like the bar it sits level with:
+                    // drag to move, double-click to zoom, while the buttons on the
+                    // right keep taking their own clicks (they're `occlude()`d).
+                    .child(crate::ui::app::title_bar_drag(
+                        controls.id("sidebar-titlebar-drag"),
+                    ))
                     .child(top_bar)
                     .child(crate::ui::scrollbar::with_vertical_scrollbar(
                         "tab-sidebar-scrollbar",

src/ui/tab_strip.rs

@@ -1518,6 +1518,25 @@ impl Tty7App {
                 // Negative off macOS only: the bar already inset us past the window
                 // controls, and there the reserve *is* the clearance.
                 .ml(px(crate::ui::app::title_bar_hug_offset()))
+                // The brand mark follows the rail's controls into the strip, so
+                // collapsing the sidebar doesn't strip the window's leading corner
+                // back to nothing (see `app::window_mark`). The group is anchored by
+                // its tiles' *hit boxes*, which start `tile_trailing_inset()` from
+                // the window edge; the mark has no box, so it adds the difference
+                // back to land its own ink on `CONTENT_INSET` like the rail's did.
+                .when_some(crate::ui::app::window_mark(), |group, mark| {
+                    group.child(
+                        div()
+                            .flex_shrink_0()
+                            .pl(px(crate::ui::app::CONTENT_INSET
+                                - crate::ui::app::tile_trailing_inset()))
+                            // The mark is solid where the tiles are line work, so it
+                            // needs more air than the 2px that separates two tiles
+                            // before the "+" beside it stops reading as part of it.
+                            .pr(px(4.))
+                            .child(mark),
+                    )
+                })
                 .child(
                     div().occlude().flex_shrink_0().child(
                         self.attach_new_tab_menu(

src/ui/theme.rs

@@ -374,6 +374,8 @@ pub(crate) fn apply_theme(mut window: Option<&mut Window>, cx: &mut App) {
         sync_native_appearance(Some(theme.dark));
     }
     let m = theme.neutrals();
+    let surfaces = theme.surfaces();
+    let sem = theme.semantics();
     let active = theme.active_palette();
     // Read before `Theme::global_mut` borrows `cx`. macOS reports the overlay /
     // legacy scroller preference here; Windows reports the accessibility
@@ -410,6 +412,13 @@ pub(crate) fn apply_theme(mut window: Option<&mut Window>, cx: &mut App) {
         opacity,
         image: theme.image.clone(),
     });
+    // Publish the interaction-state ladders. Every hand-rolled control in the
+    // shell reads its resting/hover/selected fills and label colors from here
+    // rather than picking a `Theme` colour field that looks about right — which
+    // is how the same state ended up wearing four different greys (and one
+    // invisible one) across the app. See `presets::Surface`.
+    cx.set_global(surfaces.clone());
+    cx.set_global(presets::ActiveAccent(m.accent));
 
     let t = Theme::global_mut(cx);
     // The window base carries the theme's opacity so a translucent/blurred theme
@@ -436,15 +445,23 @@ pub(crate) fn apply_theme(mut window: Option<&mut Window>, cx: &mut App) {
     // Context menus and dropdowns highlight the hovered/selected row from
     // `tokens.accent` (fill) + `accent_foreground` (text) — see gpui-component's
     // `MenuItemElement`. Left unset, that highlight falls back to the stock
-    // saturated accent, which snaps hard against this app's soft mix-based
-    // palette (the "生硬" hover). Point it at the same soft fill the command
-    // palette uses for its selected row (`list_active`, mix 0.17) so context
+    // saturated accent, which snaps hard against this app's soft palette (the
+    // "生硬" hover). Point it at the popover ladder's selected rung so context
     // menu, dropdown and palette share one hover language; keep the text at
     // `foreground` so it stays legible on the low-contrast fill instead of the
     // stock inverted accent text. The plain `accent`/`accent_foreground` fields
     // feed the same highlight in the input completion / code-action popovers, so
     // mirror both the fields and the tokens to keep every menu surface in step.
-    let accent_fill = rgb(m.list_active);
+    //
+    // NOTE the surface: menu rows paint on `popover`, not on the window
+    // background. This used to read the window ladder, which is why the menu
+    // highlight measured as little as 1.20:1 against the panel it actually sat on
+    // while nominally being the same fill that reads fine on the terminal ground.
+    //
+    // This does *not* mean "accent" — the field is gpui-component's name for a
+    // row highlight, and pointing the theme's real accent at it is what would
+    // give the saturated snap. `surfaces.popover.selected` says what it is.
+    let accent_fill = rgb(surfaces.popover.selected);
     let accent_text: Hsla = rgb(m.foreground).into();
     t.accent = accent_fill.into();
     t.accent_foreground = accent_text;
@@ -473,6 +490,135 @@ pub(crate) fn apply_theme(mut window: Option<&mut Window>, cx: &mut App) {
     t.tokens.button_primary_hover = primary_hover.into();
     t.tokens.button_primary_active = primary_active.into();
 
+    // Status colours. The last family that was still gpui-component's stock
+    // Tailwind (`red-400`, `yellow-400`, `green-400`) — a palette with no
+    // relationship to the active theme, used at 33 sites. On Dracula that put a
+    // `#f87171` delete button beside `#ff5555` terminal output: two reds, one
+    // window. On the light themes it was worse than inconsistent, at 2.45:1 —
+    // under even the non-text floor.
+    //
+    // They now come from each theme's *own* ANSI-16 (see `Theme::semantics`), so
+    // a danger marker and an error line of shell output are the same red.
+    //
+    // Each family gets three roles because the plain field and the tokens are
+    // read for different jobs: tty7's own sites use `Theme::danger` as a text /
+    // small-mark colour (a 7px status dot in the run list, a label), while
+    // gpui-component's buttons fill from `tokens.button_danger` and put
+    // `*_foreground` on top of that fill. One value cannot serve both.
+    // `ink` and `fill` each step one notch either side of themselves for
+    // hover/active — the same shape the primary family above uses.
+    let steps = |c: u32| {
+        (
+            Hsla::from(rgb(c)),
+            Hsla::from(rgb(presets::mix(c, m.background, 0.15))),
+            Hsla::from(rgb(presets::mix(c, m.foreground, 0.15))),
+        )
+    };
+
+    // ── Danger ──
+    let (ink, ink_hover, ink_active) = steps(sem.danger.ink);
+    let (fill, fill_hover, fill_active) = steps(sem.danger.fill);
+    let on_fill = Hsla::from(rgb(sem.danger.on_fill));
+    t.danger = ink;
+    t.danger_hover = ink_hover;
+    t.danger_active = ink_active;
+    t.danger_foreground = on_fill;
+    t.tokens.danger = fill.into();
+    t.tokens.danger_hover = fill_hover.into();
+    t.tokens.danger_active = fill_active.into();
+    t.tokens.danger_foreground = on_fill.into();
+    t.tokens.button_danger = fill.into();
+    t.tokens.button_danger_hover = fill_hover.into();
+    t.tokens.button_danger_active = fill_active.into();
+    t.tokens.button_danger_foreground = on_fill.into();
+
+    // ── Warning ──
+    let (ink, ink_hover, ink_active) = steps(sem.warning.ink);
+    let (fill, fill_hover, fill_active) = steps(sem.warning.fill);
+    let on_fill = Hsla::from(rgb(sem.warning.on_fill));
+    t.warning = ink;
+    t.warning_hover = ink_hover;
+    t.warning_active = ink_active;
+    t.warning_foreground = on_fill;
+    t.tokens.warning = fill.into();
+    t.tokens.warning_hover = fill_hover.into();
+    t.tokens.warning_active = fill_active.into();
+    t.tokens.warning_foreground = on_fill.into();
+    t.tokens.button_warning = fill.into();
+    t.tokens.button_warning_hover = fill_hover.into();
+    t.tokens.button_warning_active = fill_active.into();
+    t.tokens.button_warning_foreground = on_fill.into();
+
+    // ── Success ──
+    let (ink, ink_hover, ink_active) = steps(sem.success.ink);
+    let (fill, fill_hover, fill_active) = steps(sem.success.fill);
+    let on_fill = Hsla::from(rgb(sem.success.on_fill));
+    t.success = ink;
+    t.success_hover = ink_hover;
+    t.success_active = ink_active;
+    t.success_foreground = on_fill;
+    t.tokens.success = fill.into();
+    t.tokens.success_hover = fill_hover.into();
+    t.tokens.success_active = fill_active.into();
+    t.tokens.success_foreground = on_fill.into();
+    t.tokens.button_success = fill.into();
+    t.tokens.button_success_hover = fill_hover.into();
+    t.tokens.button_success_active = fill_active.into();
+    t.tokens.button_success_foreground = on_fill.into();
+
+    // ── Info ──
+    let (ink, ink_hover, ink_active) = steps(sem.info.ink);
+    let (fill, fill_hover, fill_active) = steps(sem.info.fill);
+    let on_fill = Hsla::from(rgb(sem.info.on_fill));
+    t.info = ink;
+    t.info_hover = ink_hover;
+    t.info_active = ink_active;
+    t.info_foreground = on_fill;
+    t.tokens.info = fill.into();
+    t.tokens.info_hover = fill_hover.into();
+    t.tokens.info_active = fill_active.into();
+    t.tokens.info_foreground = on_fill.into();
+    t.tokens.button_info = fill.into();
+    t.tokens.button_info_hover = fill_hover.into();
+    t.tokens.button_info_active = fill_active.into();
+    t.tokens.button_info_foreground = on_fill.into();
+
+    // Links. Unset, these resolve to near-white on dark themes and near-black on
+    // light ones — i.e. the body text colour, so a link in the Markdown preview
+    // (`ui::code_editor`, which renders through gpui-component's `TextView`)
+    // looked exactly like prose. The theme's own cyan is what a terminal user
+    // already reads as "this is a link".
+    t.link = rgb(sem.link.ink).into();
+    t.link_hover = rgb(presets::mix(sem.link.ink, m.foreground, 0.25)).into();
+    t.link_active = rgb(presets::mix(sem.link.ink, m.background, 0.20)).into();
+    t.tokens.link = Hsla::from(rgb(sem.link.ink)).into();
+    t.tokens.link_hover = Hsla::from(rgb(presets::mix(sem.link.ink, m.foreground, 0.25))).into();
+    t.tokens.link_active = Hsla::from(rgb(presets::mix(sem.link.ink, m.background, 0.20))).into();
+
+    // Switches. Three more fields nobody had set, and the reason the toggles read
+    // inverted on every dark theme:
+    //
+    // * `switch_thumb` falls back to `tokens.background` — also unset — so the
+    //   knob was gpui-component's stock near-black. On the (near-white) checked
+    //   track that is a dark knob on a light track, the opposite of every system
+    //   switch; on the dark unchecked track it disappeared entirely.
+    // * `switch` (the unchecked track) was the stock `#404040`, unrelated to the
+    //   theme.
+    //
+    // The knob takes the light end of the theme's own axis — it is a raised
+    // physical object, and both macOS modes render it near-white — and the
+    // component already draws it with `shadow_md`, which is what separates it from
+    // a light track rather than raw contrast. The unchecked track is the window
+    // ladder's `selected` rung: the same "this is filled" grey as everything else.
+    let knob = if presets::is_lighter(m.background, m.foreground) {
+        m.background
+    } else {
+        m.foreground
+    };
+    t.tokens.background = Hsla::from(rgb(m.background)).into();
+    t.tokens.switch_thumb = Hsla::from(rgb(knob)).into();
+    t.tokens.switch = Hsla::from(rgb(surfaces.window.selected)).into();
+
     t.caret = rgb(m.caret).into();
     t.selection = rgb(m.selection).into(); // text selection highlight
 
@@ -523,24 +669,73 @@ pub(crate) fn apply_theme(mut window: Option<&mut Window>, cx: &mut App) {
     // the `sidebar*` color fields — so those must be set on `tokens` or the
     // override is a no-op and the column falls back to the stock surface.
     let sidebar_bg = rgb(m.sidebar);
-    let sidebar_sel = rgb(m.sidebar_sel);
+    let sidebar_sel = rgb(surfaces.sidebar.selected);
     t.sidebar = sidebar_bg.into();
     t.tokens.sidebar = Hsla::from(sidebar_bg).into();
     t.sidebar_border = rgb(m.border).into();
-    t.sidebar_foreground = rgb(m.sidebar_fg).into();
+    t.sidebar_foreground = rgb(surfaces.sidebar.text_resting).into();
     t.sidebar_accent = sidebar_sel.into();
     t.tokens.sidebar_accent = Hsla::from(sidebar_sel).into();
-    t.sidebar_accent_foreground = rgb(m.foreground).into();
+    t.sidebar_accent_foreground = rgb(surfaces.sidebar.text_selected).into();
 
     // Flatten gpui-component's list selection highlight (used by the command
     // palette) into a single soft fill — no blue ring, no accent tint — so it
     // matches this app's minimal aesthetic instead of the stock look. Keep
     // `active_highlight` on (the alternative path tints with the shared
     // `accent`), but make the ring colour equal the fill so the box disappears.
+    //
+    // The palette and its list paint on an elevated panel, so this is the popover
+    // ladder — same reasoning as `accent` above.
     t.list.active_highlight = true;
-    t.list_active = rgb(m.list_active).into();
-    t.list_active_border = rgb(m.list_active).into();
-    t.list_hover = rgb(m.list_hover).into();
+    t.list_active = rgb(surfaces.popover.selected).into();
+    t.list_active_border = rgb(surfaces.popover.selected).into();
+    t.list_hover = rgb(surfaces.popover.hover).into();
+
+    // ── Stock widgets that were still wearing gpui-component's defaults ──────
+    //
+    // Everything above overrides a field because someone noticed it looking
+    // off-theme. The fields *nobody noticed* are the actual hazard: they silently
+    // keep the stock value, which is a fixed grey with no relationship to the
+    // active theme, so whether a control reads is down to where that theme's
+    // background happens to land relative to a hardcoded `#2f2f2f`.
+    //
+    // `input` is how issue #197 happened. Outline buttons (and inputs, selects,
+    // switches) derive their resting *and* selected fills from it, so an unset
+    // `input` put the selected segment of every segmented control at 1.03:1
+    // against its neighbours on Dracula — and inverted the direction of the
+    // change between light and dark themes. Pointing it at the window ladder ties
+    // it to the theme; `Tty7App::segmented` no longer depends on this path at all
+    // (it paints the ladder itself), but every other stock control still does.
+    t.input = rgb(surfaces.window.selected).into();
+    t.tokens.input = Hsla::from(rgb(surfaces.window.selected)).into();
+
+    // …but `input` only reaches the *outline* path, which reads the field live.
+    // The plain (non-outline) button family is derived from `input` **once**,
+    // inside the `apply_config` that `Theme::change` ran above — i.e. from the
+    // stock `#2f2f2f`, before any of this function's overrides exist — and a
+    // snapshot never sees the fix. So a plain `Button` still hovered and pressed
+    // in that grey, and `Button::selected` (the terminal search bar's `Aa` / `.*`
+    // toggles, the last two in the app) filled from `tokens.secondary_active` the
+    // same way: on Dracula, ~1.03:1 against the surface behind it. That is issue
+    // #197 again, one snapshot removed from the field that fixed it.
+    //
+    // Only the *state* rungs move — `tokens.button` (the resting fill) is left
+    // alone, so a plain button keeps the flat look it has today and only its
+    // hover/pressed/selected join the ladder.
+    let button_hover: Hsla = rgb(surfaces.window.hover).into();
+    let button_active: Hsla = rgb(surfaces.window.selected).into();
+    t.tokens.button_hover = button_hover.into();
+    t.tokens.button_active = button_active.into();
+    t.tokens.secondary_hover = button_hover.into();
+    t.tokens.secondary_active = button_active.into();
+    t.tokens.button_secondary_hover = button_hover.into();
+    t.tokens.button_secondary_active = button_active.into();
+
+    // Focus rings: the one place the theme's *real* accent belongs. A ring is ink
+    // on the background at 1–2px, which is exactly the job `legible_accent`
+    // conditions the seed for; the stock `neutral-300` was both off-theme and
+    // indistinguishable from a border.
+    t.ring = rgb(m.accent).into();
 
     // `sync_native_appearance` above may have flipped the macOS app appearance,
     // which resets the traffic-light buttons to their default (higher) position.
@@ -554,6 +749,27 @@ pub(crate) fn apply_theme(mut window: Option<&mut Window>, cx: &mut App) {
     }
 }
 
+/// A `Switch` wearing the theme's accent on its checked track.
+///
+/// Every switch in the app goes through here rather than through `Switch::new`
+/// directly. gpui-component defaults the checked track to `tokens.primary`, which
+/// tty7 tunes for *primary buttons* — a near-white on dark themes, deliberately,
+/// because a primary button is a light slab with dark text. As a switch track
+/// that same colour swallows the (near-white) knob, so the two uses genuinely
+/// need two colours and the component only offers a per-instance override.
+///
+/// The accent is the right one, and this is the one control in the app that gets
+/// it. On/off differ by *hue* here because they cannot differ by lightness: the
+/// knob has already claimed the light end of the axis, so a checked track that
+/// reads as "brighter" is a track the knob vanishes into. It is the same reason
+/// every system switch is coloured. `Neutrals::accent` is contrast-conditioned
+/// (see `presets::legible_accent`), so a seed as pale as the Light theme's
+/// `#00c2ff` still lands on a track a white knob can sit on.
+pub(crate) fn switch(id: impl Into<gpui::ElementId>, cx: &App) -> gpui_component::switch::Switch {
+    let accent = cx.global::<presets::ActiveAccent>().0;
+    gpui_component::switch::Switch::new(id).color(Hsla::from(rgb(accent)))
+}
+
 /// Apply `Config::mouse_hide_while_typing` to GPUI's cursor-hide policy: hide the
 /// pointer while typing when on, never when off. Called at startup and whenever
 /// the config changes (setter + hot-reload) so the switch takes effect live.