/* Native sticky positioning keeps the header's space in document flow. */
.site-header { position: sticky; top: 0; z-index: 30; isolation: isolate; background: var(--color-paper); }
.site-header::before { content: ""; position: absolute; inset: 0 calc((100vw - 100%) / -2); background: var(--color-paper); z-index: -1; }
:where([id], h1, h2, h3, h4, h5, h6) { scroll-margin-top: calc(var(--sticky-header-height, 104px) + 16px); }