Rotating Word Hero

A server component, one file, zero dependencies. The --vibeui-hero-017-* palette, and the theme comes from the surrounding color-scheme through light-dark(); there is no backdrop by default — the block sits on the page background. The swapping word lives in data-part="rotator": every variant sits in the same grid cell (grid-area: 1/1), so the container sizes itself to the widest variant and the width never jumps on a swap — no JS measurement needed. Each word gets an animation-delay equal to its index times the cycle length, negated: this offsets the phases so exactly one word is visible at any moment, and the infinite loop needs no state class. The rotator is aria-hidden, with a visually-hidden comma-separated list of the words next to it — otherwise a screen reader would read out every variant in a row, since opacity does not remove text from the accessibility tree. Under prefers-reduced-motion the animation stops and the first word stays visible.