diff --git a/crates/ide-core/src/settings.rs b/crates/ide-core/src/settings.rs
index f9390f0d..1b49cd81 100644
--- a/crates/ide-core/src/settings.rs
+++ b/crates/ide-core/src/settings.rs
@@ -276,6 +276,8 @@ pub struct AppearanceSettings {
     /// Apply `ui_font_family` / `ui_font_size` (otherwise the theme's).
     pub use_custom_font: bool,
     pub ui_font_family: String,
+    /// Font tried when `ui_font_family` lacks a glyph; empty = none.
+    pub ui_font_fallback: String,
     pub contrast_scrollbars: bool,
     /// Adjust colours for red-green vision deficiency.
     pub red_green_vision: bool,
@@ -326,6 +328,7 @@ impl Default for AppearanceSettings {
             zoom: 100,
             use_custom_font: false,
             ui_font_family: "Inter".into(),
+            ui_font_fallback: String::new(),
             contrast_scrollbars: false,
             red_green_vision: false,
             different_tool_window_background: false,
@@ -721,6 +724,20 @@ impl Settings {
 mod tests {
     use super::*;
 
+    #[test]
+    fn ui_font_fallback_defaults_empty_and_round_trips() {
+        let old: Settings = serde_json::from_str(r#"{"appearance":{"useCustomFont":true}}"#).unwrap();
+        assert!(old.appearance.ui_font_fallback.is_empty());
+        for family in ["", "Songti SC", "Maple Mono NF CN"] {
+            let mut settings = Settings::default();
+            settings.appearance.ui_font_fallback = family.into();
+            let json = serde_json::to_value(&settings).unwrap();
+            assert_eq!(json["appearance"]["uiFontFallback"], family);
+            let restored: Settings = serde_json::from_value(json).unwrap();
+            assert_eq!(restored.appearance.ui_font_fallback, family);
+        }
+    }
+
     #[test]
     fn tool_window_badges_default_on_and_round_trip() {
         let old: Settings = serde_json::from_str(r#"{"appearance":{"showToolWindowNames":true}}"#).unwrap();
diff --git a/src/bindings.ts b/src/bindings.ts
index 97ce0528..5c4e5a3b 100644
--- a/src/bindings.ts
+++ b/src/bindings.ts
@@ -1422,6 +1422,8 @@ export type AppearanceSettings = {
 	/**  Apply `ui_font_family` / `ui_font_size` (otherwise the theme's). */
 	useCustomFont?: boolean,
 	uiFontFamily?: string,
+	/**  Font tried when `ui_font_family` lacks a glyph; empty = none. */
+	uiFontFallback?: string,
 	contrastScrollbars?: boolean,
 	/**  Adjust colours for red-green vision deficiency. */
 	redGreenVision?: boolean,
diff --git a/src/features/settings/__tests__/behavior.test.ts b/src/features/settings/__tests__/behavior.test.ts
index 3f2cff40..e17a9eb1 100644
--- a/src/features/settings/__tests__/behavior.test.ts
+++ b/src/features/settings/__tests__/behavior.test.ts
@@ -1,7 +1,8 @@
 import { describe, expect, it } from "vitest";
 import { formatPattern, formatTimestamp } from "@/platform/dateFormat";
 import { resolveThemeId } from "@/workbench/theme";
-import { nextZoom } from "../appearanceRuntime";
+import { applyAppearanceOptions, nextZoom } from "../appearanceRuntime";
+import { validateSettings } from "../model/schema";
 import { validateAppearanceExtras, validateNotifications } from "../model/behaviorSchema";
 
 describe("appearance & behavior settings", () => {
@@ -27,6 +28,27 @@ describe("appearance & behavior settings", () => {
     expect(validateAppearanceExtras({ showToolWindowBadges: 1 }).showToolWindowBadges).toBe(true);
   });
 
+  it("keeps the UI fallback font empty by default and trims a stored one", () => {
+    expect(validateAppearanceExtras({}).uiFontFallback).toBe("");
+    expect(validateAppearanceExtras({ uiFontFallback: " 思源黑体 " }).uiFontFallback).toBe("思源黑体");
+    expect(validateAppearanceExtras({ uiFontFallback: 5 }).uiFontFallback).toBe("");
+  });
+
+  it("applies and clears the UI fallback, and removes custom fonts when disabled", () => {
+    const root = document.createElement("div");
+    const settings = validateSettings({
+      appearance: { useCustomFont: true, uiFontFamily: "Menlo", uiFontFallback: "Songti SC" },
+    });
+    applyAppearanceOptions(settings, root);
+    expect(root.style.getPropertyValue("--font-ui")).toBe('"Menlo", "Songti SC", system-ui, sans-serif');
+    settings.appearance.uiFontFallback = "";
+    applyAppearanceOptions(settings, root);
+    expect(root.style.getPropertyValue("--font-ui")).toBe('"Menlo", system-ui, sans-serif');
+    settings.appearance.useCustomFont = false;
+    applyAppearanceOptions(settings, root);
+    expect(root.style.getPropertyValue("--font-ui")).toBe("");
+  });
+
   it("formats dates with an override pattern and pretty dates", () => {
     const d = new Date(2026, 0, 5, 14, 7);
     expect(formatPattern(d, "dd.MM.yyyy")).toBe("05.01.2026");
diff --git a/src/features/settings/__tests__/dialog.test.tsx b/src/features/settings/__tests__/dialog.test.tsx
index 4a11b98c..dbdb5f02 100644
--- a/src/features/settings/__tests__/dialog.test.tsx
+++ b/src/features/settings/__tests__/dialog.test.tsx
@@ -222,6 +222,24 @@ describe("Settings dialog", () => {
     ]);
   });
 
+  it("enables, saves and clears the custom UI fallback font", async () => {
+    const dialog = await openDialog("appearance");
+    const fallback = within(dialog).getByRole("combobox", { name: "UI fallback font" });
+    const custom = within(dialog).getByRole("checkbox", { name: "Use custom font:" });
+    expect(fallback).toBeDisabled();
+    fireEvent.click(custom);
+    expect(fallback).toBeEnabled();
+    fireEvent.change(fallback, { target: { value: "Songti SC" } });
+    expect(settingsSet).not.toHaveBeenCalled();
+    await act(async () => fireEvent.click(within(dialog).getByRole("button", { name: "Apply" })));
+    expect(settingsSet).toHaveBeenCalledWith("global", "appearance.uiFontFallback", JSON.stringify("Songti SC"));
+    fireEvent.change(fallback, { target: { value: "" } });
+    await act(async () => fireEvent.click(within(dialog).getByRole("button", { name: "Apply" })));
+    expect(settingsSet).toHaveBeenCalledWith("global", "appearance.uiFontFallback", JSON.stringify(""));
+    fireEvent.click(custom);
+    expect(fallback).toBeDisabled();
+  });
+
   it("edits and saves independent custom font weights", async () => {
     const dialog = await openDialog("editor.font");
     for (const [label, value] of [
diff --git a/src/features/settings/appearanceRuntime.ts b/src/features/settings/appearanceRuntime.ts
index 3052bf65..c60c5744 100644
--- a/src/features/settings/appearanceRuntime.ts
+++ b/src/features/settings/appearanceRuntime.ts
@@ -33,7 +33,7 @@ export function applyAppearanceOptions(s: ValidSettings, root: HTMLElement = doc
     if (size === DEFAULT_SETTINGS.appearance.uiFontSize) root.style.removeProperty(name);
     else root.style.setProperty(name, `${size + delta}px`);
   }
-  if (a.useCustomFont) root.style.setProperty("--font-ui", uiFontFamily(a.uiFontFamily));
+  if (a.useCustomFont) root.style.setProperty("--font-ui", uiFontFamily(a.uiFontFamily, a.uiFontFallback));
   else root.style.removeProperty("--font-ui");
 
   flag(root, "compact", a.compactMode);
diff --git a/src/features/settings/model/behaviorSchema.ts b/src/features/settings/model/behaviorSchema.ts
index 37fadb74..d1dacd1e 100644
--- a/src/features/settings/model/behaviorSchema.ts
+++ b/src/features/settings/model/behaviorSchema.ts
@@ -20,6 +20,7 @@ export interface AppearanceExtras {
   zoom: number;
   useCustomFont: boolean;
   uiFontFamily: string;
+  uiFontFallback: string;
   contrastScrollbars: boolean;
   redGreenVision: boolean;
   differentToolWindowBackground: boolean;
@@ -72,6 +73,7 @@ export const DEFAULT_APPEARANCE_EXTRAS: AppearanceExtras = {
   zoom: 100,
   useCustomFont: false,
   uiFontFamily: "Inter",
+  uiFontFallback: "",
   contrastScrollbars: false,
   redGreenVision: false,
   differentToolWindowBackground: false,
@@ -123,6 +125,7 @@ export function validateAppearanceExtras(raw: unknown): AppearanceExtras {
     zoom: int(a.zoom, d.zoom, ZOOM_LIMITS),
     useCustomFont: b("useCustomFont"),
     uiFontFamily: typeof a.uiFontFamily === "string" && a.uiFontFamily.trim() ? a.uiFontFamily.trim() : d.uiFontFamily,
+    uiFontFallback: typeof a.uiFontFallback === "string" ? a.uiFontFallback.trim() : d.uiFontFallback,
     contrastScrollbars: b("contrastScrollbars"),
     redGreenVision: b("redGreenVision"),
     differentToolWindowBackground: b("differentToolWindowBackground"),
diff --git a/src/features/settings/pages/Behavior.module.css b/src/features/settings/pages/Behavior.module.css
index a1c511bb..0a36ad27 100644
--- a/src/features/settings/pages/Behavior.module.css
+++ b/src/features/settings/pages/Behavior.module.css
@@ -24,7 +24,7 @@
   padding: 8px 14px;
 }
 
-/* "[x] Use custom font: [Inter] Size: [13]" */
+/* Inline option groups, with custom font controls wrapping together. */
 .fontRow {
   display: flex;
   align-items: center;
@@ -37,8 +37,17 @@
 .fontInput {
   width: 220px;
 }
-.sizeLabel {
-  margin-left: 8px;
+.customFontRow {
+  flex-wrap: wrap;
+}
+.fontOption {
+  display: inline-flex;
+  align-items: center;
+  gap: 8px;
+  max-width: 100%;
+}
+.fontOption > label {
+  flex-shrink: 0;
 }
 .sizeInput {
   width: 64px;
diff --git a/src/features/settings/pages/behavior.tsx b/src/features/settings/pages/behavior.tsx
index f2a1732a..6143d3ab 100644
--- a/src/features/settings/pages/behavior.tsx
+++ b/src/features/settings/pages/behavior.tsx
@@ -181,35 +181,53 @@ function ZoomRow() {
 function CustomFontRow() {
   const [on, setOn] = useSetting<boolean>("appearance.useCustomFont");
   const [family, setFamily] = useSetting<string>("appearance.uiFontFamily");
+  const [fallback, setFallback] = useSetting<string>("appearance.uiFontFallback");
   const [size, setSize] = useSetting<number>("appearance.uiFontSize");
   const id = useId();
   const matched = useLabelMatch("Use custom font");
   return (
-    <div className={clsx(styles.fontRow, matched && styles.matched)}>
-      <Checkbox checked={on} onChange={setOn} label={<SearchLabel text="Use custom font:" />} />
-      <FontPicker label="UI font" disabled={!on} value={family} onChange={setFamily} />
-      <label className={clsx(styles.sizeLabel, !on && styles.disabled)} htmlFor={`${id}-size`}>
-        <SearchLabel text="Size:" />
-      </label>
-      {on ? (
-        <NumberInput
-          id={`${id}-size`}
-          value={size}
-          onChange={setSize}
-          {...LIMITS.uiFontSize}
-          integer
-          aria-label="UI font size"
+    <div className={clsx(styles.fontRow, styles.customFontRow, matched && styles.matched)}>
+      <span className={styles.fontOption}>
+        <Checkbox checked={on} onChange={setOn} label={<SearchLabel text="Use custom font:" />} />
+        <FontPicker label="UI font" disabled={!on} value={family} onChange={setFamily} />
+      </span>
+      <span className={styles.fontOption}>
+        <label className={clsx(!on && styles.disabled)} htmlFor={`${id}-fallback`}>
+          <SearchLabel text="Fallback font:" />
+        </label>
+        <FontPicker
+          id={`${id}-fallback`}
+          label="UI fallback font"
+          disabled={!on}
+          value={fallback}
+          onChange={setFallback}
+          allowEmpty
         />
-      ) : (
-        <Input
-          id={`${id}-size`}
-          className={styles.sizeInput}
-          value={String(size)}
-          disabled
-          aria-label="UI font size"
-          readOnly
-        />
-      )}
+      </span>
+      <span className={styles.fontOption}>
+        <label className={clsx(!on && styles.disabled)} htmlFor={`${id}-size`}>
+          <SearchLabel text="Size:" />
+        </label>
+        {on ? (
+          <NumberInput
+            id={`${id}-size`}
+            value={size}
+            onChange={setSize}
+            {...LIMITS.uiFontSize}
+            integer
+            aria-label="UI font size"
+          />
+        ) : (
+          <Input
+            id={`${id}-size`}
+            className={styles.sizeInput}
+            value={String(size)}
+            disabled
+            aria-label="UI font size"
+            readOnly
+          />
+        )}
+      </span>
     </div>
   );
 }
@@ -531,7 +549,7 @@ export const BEHAVIOR_PAGES: PageSpec[] = [
           {
             kind: "custom",
             label: "Use custom font",
-            keywords: ["UI font size", "Size", "font family"],
+            keywords: ["UI font size", "Size", "font family", "fallback font"],
             component: CustomFontRow,
           },
           { kind: "toggle", key: "appearance.contrastScrollbars", label: "Use contrast scrollbars" },
diff --git a/src/platform/fonts.test.ts b/src/platform/fonts.test.ts
index f8060c04..65cf7520 100644
--- a/src/platform/fonts.test.ts
+++ b/src/platform/fonts.test.ts
@@ -36,11 +36,13 @@ it("escapes CSS special characters without turning a family into a list", () =>
 
 describe("uiFontFamily", () => {
   it.each([
-    ["Inter", '"Inter Variable", "Inter", system-ui, sans-serif'],
-    ["JetBrains Mono", '"JetBrains Mono Variable", "JetBrains Mono", system-ui, sans-serif'],
-    [' "PingFang SC" ', '"PingFang SC", system-ui, sans-serif'],
-  ])("%j", (family, expected) => {
-    expect(uiFontFamily(family)).toBe(expected);
+    ["Inter", "", '"Inter Variable", "Inter", system-ui, sans-serif'],
+    ["JetBrains Mono", "", '"JetBrains Mono Variable", "JetBrains Mono", system-ui, sans-serif'],
+    [' "PingFang SC" ', "", '"PingFang SC", system-ui, sans-serif'],
+    ["Inter", "思源黑体", '"Inter Variable", "Inter", "思源黑体", system-ui, sans-serif'],
+    ["Inter", " ", '"Inter Variable", "Inter", system-ui, sans-serif'],
+  ])("%j + %j", (family, fallback, expected) => {
+    expect(uiFontFamily(family, fallback)).toBe(expected);
   });
 });
 
@@ -126,6 +128,16 @@ describe("macOS user font resolver", () => {
     expect(invoke).not.toHaveBeenCalled();
   });
 
+  it("loads a UI fallback through the shared macOS user font resolver", async () => {
+    const { fonts, invoke, registered } = await resolver(false);
+    const family = fonts.uiFontFamily("Inter", "Maple Mono NF CN");
+    expect(family).toBe('"Inter Variable", "Inter", "OpenIDEA User Font 0", "Maple Mono NF CN", system-ui, sans-serif');
+    expect(fonts.monoFontFamily("Inter", "Maple Mono NF CN")).toContain('"OpenIDEA User Font 0"');
+    await fonts.fontsLoaded(family, 13);
+    expect(invoke).toHaveBeenCalledExactlyOnceWith("user_font_data", { family: "Maple Mono NF CN" });
+    expect(registered).toHaveLength(3);
+  });
+
   it("detects user fonts that WKWebView exposes only to connected canvases without loading bytes", async () => {
     const { fonts, invoke, canvases } = await resolver("connected");
     expect(fonts.fontAvailable("Maple Mono NF CN")).toBe(true);
diff --git a/src/platform/fonts.ts b/src/platform/fonts.ts
index 161a9873..9acf9eb3 100644
--- a/src/platform/fonts.ts
+++ b/src/platform/fonts.ts
@@ -140,7 +140,8 @@ export async function fontsLoaded(family: string, size: number): Promise<void> {
   }
 }
 
-/** Bundled aliases also apply when selected for the interface. */
-export function uiFontFamily(family: string): string {
-  return [...familyFaces(family), "system-ui", "sans-serif"].join(", ");
+/** Bundled aliases also apply when selected for the interface; `fallback` covers glyphs `family` lacks (empty = none). */
+export function uiFontFamily(family: string, fallback = ""): string {
+  const fb = familyName(fallback);
+  return [...familyFaces(family), ...(fb ? familyFaces(fb) : []), "system-ui", "sans-serif"].join(", ");
 }
diff --git a/src/platform/locales/text/zh.json b/src/platform/locales/text/zh.json
index a7637c16..8204ccd5 100644
--- a/src/platform/locales/text/zh.json
+++ b/src/platform/locales/text/zh.json
@@ -760,6 +760,7 @@
   "Failed": "失败",
   "Failed to restart language server": "重启语言服务器失败",
   "Fallback font": "备用字体",
+  "Fallback font:": "备用字体：",
   "Fetch": "获取",
   "Fetches remotes in the background so incoming commits show in the Branches popup. Auto stops after an authentication failure.": "在后台获取远程，以便传入的提交显示在“分支”弹出窗口中。“自动”在身份验证失败后停止。",
   "Field access": "字段访问",
@@ -2223,6 +2224,7 @@
   "Merged with main toolbar": "与主工具栏合并",
   "UI Options": "UI 选项",
   "UI elements take up less screen space": "UI 元素占用更少的屏幕空间",
+  "UI fallback font": "UI 备用字体",
   "UI font": "UI 字体",
   "UI font size": "UI 字体大小",
   "Uninstalled {name}": "已卸载 {name}",