Rotate a rectangular box around its center.

CSS: A ninety-degree transform swaps the visible bounding-box width and height.

<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Example</title>
<style>
.box { width:80px; height:40px; transform:rotate(90deg); }
</style>
</head>
<body>
<div class="box">Rotated</div>
</body>
</html>

Expected output EXAMPLE

At a 1000 × 800 CSS-pixel viewport, unless another size is stated:
After rotation, the box's visible bounding rectangle is approximately 40 pixels wide and 80 pixels high.

Details

Save this complete fixture as example.html. The output describes layout or computed styles verified in Chromium. A ninety-degree transform swaps the visible bounding-box width and height.

✓ Verified

Tested on Ubuntu 24.04.5 LTS · 2026-11-02 18:10:05 UTC · Chromium 141.0.7390.37 · libc6 2.39-0ubuntu8.9; Playwright 1.56.0

Test inputs, results and environment

The exact published code ran in a dedicated Linux test container with prepared inputs. Unprivileged snippet process, external networking disabled, read-only root filesystem, and a fresh temporary working directory. Fixtures and output records are isolated from the application database. Testing covers this example and its stated checks, not every input, operating system, or runtime version. The Linux container shares its host's kernel; this is not a native Windows test.

Architecture / host kernel: x86_64 / 6.18.54.1-microsoft-standard-WSL2
Snippet identity / locale: uid=65534, gid=65534 (unprivileged) / C.UTF-8
Interpreter invocation: Chromium: open example.html; execute the published browser assertions
Container image ID: sha256:32dc2d998158b6554c99b73b533f423696a0f3e31e8cbea9db10b5eee9a2fadd
Code SHA-256: 1ba9c429e1e90d10a91bf80c3a50ee6790ae98261f4c5023cb2ec8d22db5361f
Dependencies: libc6 2.39-0ubuntu8.9; Playwright 1.56.0

Test input setup

These are the prepared inputs used by the test harness. See Details above for the prerequisites and how to run this example.

# No input files required.

Observed standard output

Expected output describes the rendered page. The standard-output record below is the browser test harness receipt; the additional assertions check the result and interactions.

Rotate a rectangular box around its center: browser checks passed.

Exit code: 0. Standard error: empty. Validation: Shape/content assertions. System-dependent values above are one recorded run.

Additional assertions that passed

Checks recorded by the test harness. Where Python assertions are shown, browser cases use Playwright and simulator cases may inspect pin transitions: result.stdout is captured output, work is the temporary directory, and Path is pathlib.Path. The harness also imports json and csv.

a=await page.locator('.box').bounding_box()
assert abs(a['width']-40)<1 and abs(a['height']-80)<1