diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 5567a0d8..33fd7c8b 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -303,7 +303,7 @@ jobs:
     env:
       PLAYWRIGHT_ARTIFACT_NAMESPACE: e2e-full-${{ matrix.browser }}-${{ matrix.device }}-${{ matrix.role }}
       PLAYWRIGHT_REPORTER_MODE: line-html
-      PLAYWRIGHT_WORKERS: ${{ matrix.browser == 'firefox' && '1' || '2' }}
+      PLAYWRIGHT_WORKERS: 1
       PLAYWRIGHT_VIDEO_MODE: off
     steps:
       - name: Repair self-hosted workspace permissions
diff --git a/README.md b/README.md
index b6149820..d2aa18b4 100644
--- a/README.md
+++ b/README.md
@@ -138,9 +138,11 @@ PLAYWRIGHT_PARALLEL_WORKERS_WEBKIT=1
 The runner fails fast if the combined worker count exceeds 5.
 
 GitHub Actions keeps the full browser/device/role matrix stable by capping full-suite
-matrix parallelism at 2 jobs, wrapping Docker Playwright runs with `systemd-inhibit`
-when available, and setting `PLAYWRIGHT_VIDEO_MODE=off` for the full matrix. Traces
-and screenshots are still retained on failure.
+matrix parallelism at 2 jobs, running each full slice with `PLAYWRIGHT_WORKERS=1`,
+wrapping Docker Playwright runs with `systemd-inhibit` when available, and setting
+`PLAYWRIGHT_VIDEO_MODE=off` for the full matrix. The E2E network harness stubs the
+external Font Awesome stylesheet so WebKit page loads do not depend on CDN/TLS
+availability. Traces and screenshots are still retained on failure.
 
 Artifacts and summaries:
 
diff --git a/tests/e2e/support/network.js b/tests/e2e/support/network.js
index bbff3ca2..293ea4ba 100644
--- a/tests/e2e/support/network.js
+++ b/tests/e2e/support/network.js
@@ -5831,6 +5831,17 @@ export async function mockApi(page, options = {}) {
     ...(options.sessionData?.notifications || {}),
   };
 
+  await page.route(
+    /https:\/\/cdnjs\.cloudflare\.com\/ajax\/libs\/font-awesome\/.*\/css\/all\.min\.css(?:[?#].*)?$/i,
+    async (route) => {
+      await route.fulfill({
+        status: 200,
+        contentType: "text/css",
+        body: "",
+      });
+    }
+  );
+
   await page.route(/https:\/\/cdn\.example\.test\/.*$/i, async (route) => {
     const request = route.request();
     if (request.method() !== "GET") {
diff --git a/tests/unit/playwright-full-workflow.spec.js b/tests/unit/playwright-full-workflow.spec.js
index f594530e..883946f1 100644
--- a/tests/unit/playwright-full-workflow.spec.js
+++ b/tests/unit/playwright-full-workflow.spec.js
@@ -4,6 +4,7 @@ import { describe, expect, it } from "vitest";
 
 const root = process.cwd();
 const workflowSource = () => readFileSync(join(root, ".github/workflows/tests.yml"), "utf8");
+const networkFixtureSource = () => readFileSync(join(root, "tests/e2e/support/network.js"), "utf8");
 
 describe("Playwright full E2E workflow grouping", () => {
   it("orders full-suite matrix dimensions by browser, device, then role", () => {
@@ -33,6 +34,7 @@ describe("Playwright full E2E workflow grouping", () => {
     const source = workflowSource();
 
     expect(source).toMatch(/e2e-full:[\s\S]*?max-parallel: 2/u);
+    expect(source).toMatch(/e2e-full:[\s\S]*?PLAYWRIGHT_WORKERS: 1/u);
     expect(source).toMatch(/e2e-full:[\s\S]*?PLAYWRIGHT_VIDEO_MODE: off/u);
     expect(source).toContain("scripts/ci/with-systemd-inhibit.sh");
     expect(source).toContain("scripts/ci/runner-diagnostics.sh");
@@ -45,4 +47,11 @@ describe("Playwright full E2E workflow grouping", () => {
     expect(source).toContain('"retain-on-failure"');
     expect(source).toContain('"on-first-retry"');
   });
+
+  it("stubs external stylesheets that can block WebKit page load", () => {
+    const source = networkFixtureSource();
+
+    expect(source).toContain("cdnjs\\.cloudflare\\.com");
+    expect(source).toContain('contentType: "text/css"');
+  });
 });