Drifting clouds

Clouds of different sizes slowly cross the sky behind the text, each at its own speed, as seen from a balloon basket: a calm, airy mood for an outdoor activity, a travel agency, a local weather page, a holiday cottage or a wellbeing app. Each cloud is a single rounded element drawn and animated in CSS (transform), with no image or script, and the decoration is hidden from screen readers. A checkbox pauses the sky, as WCAG 2.2.2 requires. A sunrise sky in light mode, a night sky in dark mode, AA contrast in both. With prefers-reduced-motion the clouds stay still.