Choose the smaller of a fixed and viewport-relative size.
CSS: Min selects whichever supplied length is smaller at the current viewport.
<!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:min(400px,50vw); }
</style>
</head>
<body>
<div class="box">Content</div>
</body>
</html>Expected output EXAMPLE
At a 1000 × 800 CSS-pixel viewport, unless another size is stated: The “.box” element has a rendered width of 400 pixels. At a 390-pixel-wide viewport: The “.box” element has a rendered width of 195 pixels.
Details
Save this complete fixture as example.html. The output describes layout or computed styles verified in Chromium. Min selects whichever supplied length is smaller at the current viewport.
Tested on Ubuntu 24.04.5 LTS · · 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
8cc7de64782e85a4245a0e80d0a030448aaa51fdeb5dc977fb2fd32cd01c2b36- 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.
Choose the smaller of a fixed and viewport-relative size: 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.
assert (await page.locator('.box').bounding_box())['width']==400
await page.set_viewport_size({'width':390,'height':844})
assert (await page.locator('.box').bounding_box())['width']==195