Commit 3e60fecf39f37faaca9bdf37e64b7a58229ea547 | the-knife

author	shivam <91240327+shivamhwp@users.noreply.github.com> 2026-10-02 10:34:17+05:30
committer	GitHub <noreply@github.com> 2026-10-02 10:34:17+05:30
log	3e60fecf39f37faaca9bdf37e64b7a58229ea547
tree	eff937afe5b4895d12c7317065015095bf248749
parent	2731929610ecb64617ff5e066980302da328f658
signature	Signed by PGP key B5690EEEBB952194

fix(desktop): markdown pages no longer render invisible in the dark-mode browser (#14601)

Co-authored-by: PR Batch Tester <agent@local.test>
Co-authored-by: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

2 files changed, 28 insertions(+), 1 deletions(-)

apps
- desktop
  - src
    preview
    Manager.test.ts
    Manager.ts

apps/desktop/src/preview/Manager.test.ts+15-1

 @@ -1601,7 +1601,7 @@ describe("PreviewManager", () => {
     ),
   );
-  effectIt.effect("emulates prefers-color-scheme and re-applies it across webview swaps", () =>
+  effectIt.effect("re-applies opaque base and color scheme across webview swaps", () =>
     withManager((manager) =>
       Effect.gen(function* () {
         const makeWebContents = (id: number) => {
 @@ -1650,6 +1650,16 @@ describe("PreviewManager", () => {
         yield* manager.registerWebview("tab_scheme", 42);
         yield* Effect.yieldNow;
+        // Guests start with a transparent base; dark-scheme pages need an opaque
+        // one or Chromium skips their dark canvas.
+        const opaqueBase = {
+          color: { r: 255, g: 255, b: 255, a: 1 },
+        };
+        expect(first.sendCommand).toHaveBeenCalledWith(
+          "Emulation.setDefaultBackgroundColorOverride",
+          opaqueBase,
+        );
         yield* manager.setColorScheme("tab_scheme", "dark");
         expect(first.sendCommand).toHaveBeenCalledWith("Emulation.setEmulatedMedia", {
 @@ -1662,6 +1672,10 @@ describe("PreviewManager", () => {
         yield* manager.registerWebview("tab_scheme", 43);
         yield* Effect.yieldNow;
+        expect(replacement.sendCommand).toHaveBeenCalledWith(
+          "Emulation.setDefaultBackgroundColorOverride",
+          opaqueBase,
+        );
         expect(replacement.sendCommand).toHaveBeenCalledWith("Emulation.setEmulatedMedia", {
           features: [{ name: "prefers-color-scheme", value: "dark" }],
         });

apps/desktop/src/preview/Manager.ts+13

...	@@ -1418,6 +1418,19 @@ const makeNativeOperations = Effect.fn("PreviewManager.makeOperations")(function	...	@@ -1418,6 +1418,19 @@ const makeNativeOperations = Effect.fn("PreviewManager.makeOperations")(function
1418	),	1418	),
1419	{ concurrency: "unbounded", discard: true },	1419	{ concurrency: "unbounded", discard: true },
1420	);	1420	);
		1421	// Electron gives `<webview>` guests a transparent base background, and
		1422	// Chromium only paints a dark canvas for dark color-scheme pages over an
		1423	// opaque base. Without this, dark-scheme pages with no background of
		1424	// their own (text/plain, e.g. .md files) render white text on white.
		1425	// White matches the webview's existing white backing, so light pages look
		1426	// the same; Chromium still swaps in its dark canvas for dark-scheme pages.
		1427	yield* attemptPromise(
		1428	{ operation: "initializeDebugger.defaultBackground", webContentsId: wc.id },
		1429	() =>
		1430	wcDebugger.sendCommand("Emulation.setDefaultBackgroundColorOverride", {
		1431	color: { r: 255, g: 255, b: 255, a: 1 },
		1432	}),
		1433	);
1421	return [	1434	return [
1422	control,	1435	control,
1423	replaceMap(sessions, (copy) => {	1436	replaceMap(sessions, (copy) => {