<!doctype html> <html lang=en> <meta charset=utf-8> <title>CSS-contain test reference</title> <link rel="author" title="Florian Rivoal" href="https://florian.rivoal.net"> <style> html, body, p { margin: 0; width: 300px; height: 200px; } </style> <p>Test passes if there is no red.