diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5188dcf..c7fe9a2 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -18,11 +18,9 @@ jobs:
       - uses: actions/setup-node@v4
         with:
           node-version: ${{ matrix.node-version }}
-      - name: Syntax check
-        run: |
-          node --check server.js
-          node --check public/app.js
-      - name: Privacy audit
-        run: npm run audit:privacy
-      - name: Smoke test
-        run: npm test
+      - name: Install dependencies
+        run: npm ci
+      - name: Install Chromium
+        run: npx playwright install --with-deps chromium
+      - name: Full check
+        run: npm run check
diff --git a/docs/development.md b/docs/development.md
index 5d0ab22..44aa1ef 100644
--- a/docs/development.md
+++ b/docs/development.md
@@ -27,6 +27,13 @@ node --check server.js
 node --check public/app.js
 npm run audit:privacy
 npm test
+npm run test:browser
+```
+
+The browser smoke check uses Playwright with Chromium. After a fresh install, run:
+
+```bash
+npx playwright install chromium
 ```
 
 ## Live Check
diff --git a/package-lock.json b/package-lock.json
new file mode 100644
index 0000000..1c62e14
--- /dev/null
+++ b/package-lock.json
@@ -0,0 +1,66 @@
+{
+  "name": "claw-space",
+  "version": "0.1.6",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "claw-space",
+      "version": "0.1.6",
+      "license": "MIT",
+      "devDependencies": {
+        "playwright": "^1.55.1"
+      },
+      "engines": {
+        "node": ">=20"
+      }
+    },
+    "node_modules/fsevents": {
+      "version": "2.3.2",
+      "resolved": "https://registry.npmjs.org/fsevents/-/fsevents-2.3.2.tgz",
+      "integrity": "sha512-xiqMQR4xAeHTuB9uWm+fFRcIOgKBMiOBP+eXiyT7jsgVCq1bkVygt00oASowB7EdtpOHaaPgKt812P9ab+DDKA==",
+      "dev": true,
+      "hasInstallScript": true,
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "darwin"
+      ],
+      "engines": {
+        "node": "^8.16.0 || ^10.6.0 || >=11.0.0"
+      }
+    },
+    "node_modules/playwright": {
+      "version": "1.60.0",
+      "resolved": "https://registry.npmjs.org/playwright/-/playwright-1.60.0.tgz",
+      "integrity": "sha512-hheHdokM8cdqCb0lcE3s+zT4t4W+vvjpGxsZlDnikarzx8tSzMebh3UiFtgqwFwnTnjYQcsyMF8ei2mCO/tpeA==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "dependencies": {
+        "playwright-core": "1.60.0"
+      },
+      "bin": {
+        "playwright": "cli.js"
+      },
+      "engines": {
+        "node": ">=18"
+      },
+      "optionalDependencies": {
+        "fsevents": "2.3.2"
+      }
+    },
+    "node_modules/playwright-core": {
+      "version": "1.60.0",
+      "resolved": "https://registry.npmjs.org/playwright-core/-/playwright-core-1.60.0.tgz",
+      "integrity": "sha512-9bW6zvX/m0lEbgTKJ6YppOKx8H3VOPBMOCFh2irXFOT4BbHgrx5hPjwJYLT40Lu+4qtD36qKc/Hn56StUW57IA==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "bin": {
+        "playwright-core": "cli.js"
+      },
+      "engines": {
+        "node": ">=18"
+      }
+    }
+  }
+}
diff --git a/package.json b/package.json
index 7960f5b..81ad93a 100644
--- a/package.json
+++ b/package.json
@@ -21,11 +21,15 @@
   ],
   "scripts": {
     "audit:privacy": "node scripts/privacy-audit.js",
-    "check": "node --check server.js && node --check public/app.js && npm run audit:privacy && npm test",
+    "check": "node --check server.js && node --check public/app.js && npm run audit:privacy && npm test && npm run test:browser",
     "start": "node server.js",
     "test": "node tests/smoke.js",
+    "test:browser": "node tests/browser-smoke.js",
     "test:live": "node tests/live.js"
   },
+  "devDependencies": {
+    "playwright": "^1.55.1"
+  },
   "engines": {
     "node": ">=20"
   }
diff --git a/tests/browser-smoke.js b/tests/browser-smoke.js
new file mode 100644
index 0000000..5ecfb19
--- /dev/null
+++ b/tests/browser-smoke.js
@@ -0,0 +1,72 @@
+'use strict';
+
+const assert = require('assert');
+
+process.env.OPENCLAW_WEB_UI_MOCK = '1';
+
+const { chromium } = require('playwright');
+const { createApp } = require('../server');
+
+async function expectDashboard(page, baseUrl, width, height) {
+  await page.setViewportSize({ width, height });
+  await page.goto(baseUrl, { waitUntil: 'load' });
+
+  const localAccess = page.locator('#securityStatusCard');
+  await localAccess.waitFor({ state: 'visible', timeout: 10000 });
+  await page.locator('#tab-dashboard').waitFor({ state: 'visible', timeout: 10000 });
+
+  const heading = await localAccess.getByText('Local Access', { exact: true }).count();
+  assert.equal(heading, 1, `missing Local Access panel at ${width}x${height}`);
+
+  const overflow = await page.evaluate(() => {
+    const root = document.documentElement;
+    const dashboard = document.querySelector('#tab-dashboard');
+    const surface = dashboard ? dashboard.scrollWidth - dashboard.clientWidth : 0;
+    return {
+      pageOverflow: Math.max(0, root.scrollWidth - root.clientWidth),
+      surfaceOverflow: Math.max(0, surface)
+    };
+  });
+
+  assert.equal(
+    overflow.pageOverflow,
+    0,
+    `horizontal page overflow at ${width}x${height}: ${overflow.pageOverflow}px`
+  );
+  assert.equal(
+    overflow.surfaceOverflow,
+    0,
+    `dashboard overflow at ${width}x${height}: ${overflow.surfaceOverflow}px`
+  );
+}
+
+async function main() {
+  const app = createApp();
+  await new Promise((resolve, reject) => {
+    app.once('error', reject);
+    app.listen(0, '127.0.0.1', resolve);
+  });
+
+  try {
+    const address = app.address();
+    const port = typeof address === 'object' && address ? address.port : 0;
+    const baseUrl = `http://127.0.0.1:${port}`;
+    const browser = await chromium.launch({ headless: true });
+    try {
+      const page = await browser.newPage();
+      await expectDashboard(page, baseUrl, 1280, 900);
+      await expectDashboard(page, baseUrl, 390, 844);
+    } finally {
+      await browser.close();
+    }
+  } finally {
+    await new Promise((resolve) => app.close(resolve));
+  }
+
+  console.log('browser-smoke-ok');
+}
+
+main().catch((err) => {
+  console.error(err);
+  process.exit(1);
+});