A full-height section sized with `100vh`
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Rule · bucket: mechanical · severity: warning · detector: viewport-height · since: v0.10.0
Section: Things to avoid
Group: Spacing and layout

Forbidden:
  `min-height: 100vh` on a hero, a sign-in screen or an app shell

Instead:
  `min-height: 100svh`. Use `dvh` only for an element that must follow the browser bars as they show and hide. If older browsers matter, keep `100vh` as the line **before** it, as a fallback.

On a phone, `100vh` is the height with the browser's bars hidden. While they are showing — which is when the page first loads — the bottom of a "full-height" section is under the toolbar, and the call to action placed at its foot is exactly what cannot be seen.
`svh` is the default because it does not change: `dvh` resizes as the bars move, which makes the content jump while the reader scrolls.