/* 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); }

/* Shared Hugo equivalents of the Nova navigation, Sheet and card primitives. */
:root {
  --background: var(--color-paper);
  --foreground: var(--color-ink);
  --card: var(--color-white);
  --muted-foreground: var(--color-ink-soft);
  --border: var(--color-rule);
  --ring: var(--color-focus);
  --navigation-ease: cubic-bezier(.4, 0, .2, 1);
  --sticky-header-height: 72px;
}
.site-header { height: 72px; min-height: 72px; padding-block: 0; display: flex; gap: 24px; }
.site-header > .brand { flex-shrink: 0; }
.site-header .navigation { position: static; margin: 0 0 0 auto; padding: 0; border: 0; width: auto; max-width: none; background: transparent; color: var(--foreground); overflow: visible; }
.site-header .navigation[open] { display: block; }
.site-header .main-nav { display: flex; flex-wrap: nowrap; justify-content: flex-end; gap: 12px; font-size: .75rem; }
.site-header .main-nav a { display: flex; align-items: center; min-height: 44px; }
.site-header .nav-toggle, .site-header .nav-close { display: none; }
.start { padding-block: 64px; }
.start .guide-grid { grid-template-columns: repeat(6, minmax(0, 1fr)); gap: 16px; margin-top: 32px; }
.start .guide-card { grid-column: span 2; padding: 24px; min-height: 0; }
.start .guide-card:nth-child(n+4) { grid-column: span 3; }
.start .guide-card h3 { margin: 24px 0 8px; }
.start .guide-card a { padding-top: 24px; min-height: 44px; }
.hub-group { padding-block: 64px 0; }
.hub-group-heading h2 { font-size: var(--step-2); line-height: 1.2; margin: 0; }
.hub-group-heading p { margin: 16px 0 0; color: var(--muted-foreground); }
.hub-group .article-grid { margin-top: 24px; gap: 24px; }
.hub-group .article-grid article { padding: 24px; display: flex; flex-direction: column; }
.hub-group .article-grid h3 { font-size: 1.8rem; line-height: 1.15; font-weight: 500; margin: 12px 0; }
.hub-group .article-grid .read-link { margin-top: auto; padding-top: 16px; }
.hub-all { margin: 24px 0 0; }
.article-breadcrumb { flex-wrap: wrap; }
@media (max-width: 1279px) {
  .site-header .nav-toggle, .site-header .nav-close { display: flex; align-items: center; gap: 8px; min-height: 44px; }
  .site-header .nav-close { margin: 0 0 24px auto; border: 0; padding: 8px; background: transparent; color: var(--foreground); cursor: pointer; }
  .site-header .navigation { position: fixed; inset: 0 0 0 auto; margin: 0; height: 100dvh; max-height: none; width: min(88vw, 384px); padding: 24px; background: var(--background); border-left: 1px solid var(--border); overflow-y: auto; box-shadow: 0 4px 16px color-mix(in srgb, var(--foreground) 12%, transparent); }
  .site-header .navigation:not(:modal) { display: none; }
  .site-header .navigation:modal { display: block; animation: navigation-enter 220ms var(--navigation-ease); }
  .navigation::backdrop { background: color-mix(in srgb, var(--foreground) 45%, transparent); }
  .site-header .main-nav { display: flex; flex-direction: column; align-items: stretch; gap: 8px; font-size: 1rem; }
  .site-header .main-nav a { white-space: normal; padding: 8px; }
  body:has(.navigation:modal) { overflow: hidden; }
}
@keyframes navigation-enter { from { transform: translateX(100%); } to { transform: translateX(0); } }
@media (max-width: 850px) {
  .start { padding-block: 40px; }
  .start .guide-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .start .guide-card:nth-child(n) { grid-column: auto; }
  .start .guide-card:last-child { grid-column: 1 / -1; }
  .hub-group { padding-top: 40px; }
}
@media (max-width: 540px) {
  .start .guide-grid { grid-template-columns: 1fr; }
  .start .guide-card:last-child { grid-column: auto; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .navigation:modal { animation: none !important; }
}