diff --git a/external/builder/builder.mjs b/external/builder/builder.mjs
index 5f6c0551c..376fbda8e 100644
--- a/external/builder/builder.mjs
+++ b/external/builder/builder.mjs
@@ -42,6 +42,12 @@ function preprocess(inFilename, outFilename, defines) {
     return content.replaceAll(
       /^\s*@import\s+url\(([^)]+)\);\s*$/gm,
       function (all, url) {
+        if (defines.GECKOVIEW) {
+          switch (url) {
+            case "annotation_editor_layer_builder.css":
+              return "";
+          }
+        }
         const file = path.join(path.dirname(baseUrl), url);
         const imported = fs.readFileSync(file, "utf8").toString();
         return expandCssImports(imported, file);
diff --git a/gulpfile.mjs b/gulpfile.mjs
index deafd10ad..4efed955d 100644
--- a/gulpfile.mjs
+++ b/gulpfile.mjs
@@ -1354,6 +1354,7 @@ gulp.task(
       console.log();
       console.log("### Building mozilla-central extension");
       const defines = builder.merge(DEFINES, { MOZCENTRAL: true });
+      const gvDefines = builder.merge(defines, { GECKOVIEW: true });
 
       const MOZCENTRAL_DIR = BUILD_DIR + "mozcentral/",
         MOZCENTRAL_EXTENSION_DIR = MOZCENTRAL_DIR + "browser/extensions/pdfjs/",
@@ -1405,7 +1406,7 @@ gulp.task(
         preprocessHTML("web/viewer.html", defines).pipe(
           gulp.dest(MOZCENTRAL_CONTENT_DIR + "web")
         ),
-        preprocessHTML("web/viewer-geckoview.html", defines).pipe(
+        preprocessHTML("web/viewer-geckoview.html", gvDefines).pipe(
           gulp.dest(MOZCENTRAL_CONTENT_DIR + "web")
         ),
 
@@ -1414,7 +1415,7 @@ gulp.task(
           .pipe(replaceMozcentralCSS())
           .pipe(gulp.dest(MOZCENTRAL_CONTENT_DIR + "web")),
 
-        preprocessCSS("web/viewer-geckoview.css", defines)
+        preprocessCSS("web/viewer-geckoview.css", gvDefines)
           .pipe(postcss([autoprefixer(MOZCENTRAL_AUTOPREFIXER_CONFIG)]))
           .pipe(replaceMozcentralCSS())
           .pipe(gulp.dest(MOZCENTRAL_CONTENT_DIR + "web")),
diff --git a/web/pdf_viewer.css b/web/pdf_viewer.css
index fd875a8ed..d4d83a4c1 100644
--- a/web/pdf_viewer.css
+++ b/web/pdf_viewer.css
@@ -15,6 +15,7 @@
 @import url(text_layer_builder.css);
 @import url(annotation_layer_builder.css);
 @import url(xfa_layer_builder.css);
+/* Ignored in GECKOVIEW builds: */
 @import url(annotation_editor_layer_builder.css);
 
 :root {