diff --git a/src/features/settings/dialog/SettingsDialog.module.css b/src/features/settings/dialog/SettingsDialog.module.css
index 0a1105ab..a9ab4292 100644
--- a/src/features/settings/dialog/SettingsDialog.module.css
+++ b/src/features/settings/dialog/SettingsDialog.module.css
@@ -204,9 +204,10 @@
   color: var(--fg);
 }
 /* Linux draws no shadow for a frameless window (Wayland/KDE give undecorated
-   windows no CSD), so mark its edge in CSS instead. */
+   windows no CSD), so mark its edge in CSS instead. --border-window alone is
+   near-invisible on the dark theme, so blend the foreground tone into it. */
 .windowEdge {
-  box-shadow: inset 0 0 0 1px var(--border-window);
+  box-shadow: inset 0 0 0 1px color-mix(in srgb, var(--fg) 32%, var(--border-window));
 }
 .windowBody {
   flex: 1;