gulpfile.mjs

@@ -1431,7 +1431,6 @@ gulp.task(
           .pipe(
             postcss([
               discardCommentsCSS(),
-              postcssDarkThemeClass(),
               autoprefixer(MOZCENTRAL_AUTOPREFIXER_CONFIG),
             ])
           )
@@ -1442,7 +1441,6 @@ gulp.task(
           .pipe(
             postcss([
               discardCommentsCSS(),
-              postcssDarkThemeClass(),
               autoprefixer(MOZCENTRAL_AUTOPREFIXER_CONFIG),
             ])
           )

web/app.js

@@ -202,40 +202,39 @@ const PDFViewerApplication = {
       await this._parseHashParams();
     }
 
-    let mode;
+    if (typeof PDFJSDev === "undefined" || !PDFJSDev.test("MOZCENTRAL")) {
-    switch (AppOptions.get("viewerCssTheme")) {
+      let mode;
-      case 1:
+      switch (AppOptions.get("viewerCssTheme")) {
-        mode = "is-light";
+        case 1:
-        break;
+          mode = "is-light";
-      case 2:
+          break;
-        mode = "is-dark";
+        case 2:
-        break;
+          mode = "is-dark";
-    }
+          break;
-    if (mode) {
-      document.documentElement.classList.add(mode);
-    }
-
-    if (typeof PDFJSDev === "undefined" || PDFJSDev.test("TESTING")) {
-      if (AppOptions.get("enableFakeMLManager")) {
-        this.mlManager =
-          MLManager.getFakeMLManager?.({
-            enableGuessAltText: AppOptions.get("enableGuessAltText"),
-            enableAltTextModelDownload: AppOptions.get(
-              "enableAltTextModelDownload"
-            ),
-          }) || null;
       }
-    } else if (PDFJSDev.test("MOZCENTRAL")) {
+      if (mode) {
-      if (AppOptions.get("enableAltText")) {
+        document.documentElement.classList.add(mode);
-        // We want to load the image-to-text AI engine as soon as possible.
-        this.mlManager = new MLManager({
-          enableGuessAltText: AppOptions.get("enableGuessAltText"),
-          enableAltTextModelDownload: AppOptions.get(
-            "enableAltTextModelDownload"
-          ),
-          altTextLearnMoreUrl: AppOptions.get("altTextLearnMoreUrl"),
-        });
       }
+      if (typeof PDFJSDev === "undefined" || PDFJSDev.test("TESTING")) {
+        if (AppOptions.get("enableFakeMLManager")) {
+          this.mlManager =
+            MLManager.getFakeMLManager?.({
+              enableGuessAltText: AppOptions.get("enableGuessAltText"),
+              enableAltTextModelDownload: AppOptions.get(
+                "enableAltTextModelDownload"
+              ),
+            }) || null;
+        }
+      }
+    } else if (AppOptions.get("enableAltText")) {
+      // We want to load the image-to-text AI engine as soon as possible.
+      this.mlManager = new MLManager({
+        enableGuessAltText: AppOptions.get("enableGuessAltText"),
+        enableAltTextModelDownload: AppOptions.get(
+          "enableAltTextModelDownload"
+        ),
+        altTextLearnMoreUrl: AppOptions.get("altTextLearnMoreUrl"),
+      });
     }
 
     // Ensure that the `L10n`-instance has been initialized before creating

web/app_options.js

@@ -334,11 +334,6 @@ const defaultOptions = {
     value: 1,
     kind: OptionKind.VIEWER + OptionKind.PREFERENCE,
   },
-  viewerCssTheme: {
-    /** @type {number} */
-    value: typeof PDFJSDev !== "undefined" && PDFJSDev.test("CHROME") ? 2 : 0,
-    kind: OptionKind.VIEWER + OptionKind.PREFERENCE,
-  },
   viewOnLoad: {
     /** @type {boolean} */
     value: 0,
@@ -494,6 +489,11 @@ if (typeof PDFJSDev === "undefined" || !PDFJSDev.test("MOZCENTRAL")) {
         : "../build/pdf.sandbox.mjs",
     kind: OptionKind.VIEWER,
   };
+  defaultOptions.viewerCssTheme = {
+    /** @type {number} */
+    value: typeof PDFJSDev !== "undefined" && PDFJSDev.test("CHROME") ? 2 : 0,
+    kind: OptionKind.VIEWER + OptionKind.PREFERENCE,
+  };
   defaultOptions.enableFakeMLManager = {
     /** @type {boolean} */
     value: true,