/* Shared static header. Separate class names keep legacy page styles out. */
.site-header.shared-header {
  position: fixed; inset: 0 0 auto; z-index: 90;
  background: color-mix(in srgb, var(--bg) 96%, transparent) !important;
  border-bottom: 1px solid var(--border); box-shadow: none;
  backdrop-filter: blur(12px);
}
.site-header-inner {
  display: flex; align-items: center; gap: 24px; min-height: 80px;
  max-width: 1280px; margin: auto; padding: 0 32px;
}
.site-brand { display: inline-flex; align-items: center; gap: 12px; flex-shrink: 0; color: var(--fg); text-decoration: none; font-size: 20px; font-weight: 750; letter-spacing: -.04em; }
.site-signet { --signet-height: 34px; position: relative; display: block; flex: none; height: var(--signet-height); width: calc(var(--signet-height) * 455 / 850); overflow: hidden; }
.site-signet img { position: absolute; max-width: none; width: auto; height: calc(var(--signet-height) * 1254 / 850); top: calc(var(--signet-height) * -202 / 850); left: calc(var(--signet-height) * -400 / 850); }
.site-nav { --navigation-copy: #b4c0ce; display: flex; align-items: center; flex: 1; gap: 22px; margin-left: 32px; min-width: 0; }
.site-nav a { display: inline-flex; align-items: center; justify-content: center; gap: 8px; min-height: 44px; color: var(--navigation-copy); text-decoration: none; font-size: 14px; font-weight: 550; white-space: nowrap; transition: color .2s ease, background-color .2s ease; }
html[data-theme="light"] .site-nav { --navigation-copy: #475569; }
.site-nav a:hover, .site-nav a.is-active { color: var(--fg); }
.site-nav a.is-active { text-decoration: underline; text-underline-offset: 6px; text-decoration-color: var(--accent); }
.site-nav .site-learn { margin-left: auto; padding: 0 12px; min-height: 38px; border: 1px solid var(--border-strong); border-radius: 8px; color: var(--fg); font-size: 13px; }
.site-learn svg { width: 16px; height: 16px; stroke: currentColor; stroke-width: 1.2; }
.site-nav .site-learn:hover { background: color-mix(in srgb, var(--accent) 8%, transparent); }
.site-nav .site-check { padding: 0 18px; border-radius: 10px; color: #051015; background: linear-gradient(135deg,#6bc8d5,var(--accent)); font-weight: 650; }
.site-nav .site-check:hover { color: #051015; background: #8eddea; }
.site-theme { display: inline-grid; place-items: center; flex: none; width: 44px; height: 44px; padding: 12px; border: 0; background: transparent; color: var(--fg); cursor: pointer; }
.site-theme svg { width: 20px; height: 20px; stroke: currentColor; fill: currentColor; stroke-width: 1.3; }
.shared-header a:focus-visible, .site-theme:focus-visible, .site-menu-control:focus-visible, .site-menu-dialog a:focus-visible { outline: 2px solid var(--accent); outline-offset: 5px; }
.site-menu-control { display: none; position: fixed; z-index: 100; top: 18px; right: 24px; width: 46px; height: 46px; padding: 0; border: 1px solid var(--border-strong); border-radius: 14px; background: var(--bg); color: var(--fg); cursor: pointer; align-items: center; justify-content: center; flex-direction: column; gap: 6px; }
.site-menu-control span { width: 20px; height: 1.5px; background: currentColor; }
.home-page.navigation-ready:not(.intro-passed) > .site-menu-control, .site-menu-dialog .menu-close { display: flex; }
.site-menu-dialog { position: fixed; inset: 0; width: 100%; max-width: none; height: 100dvh; max-height: none; margin: 0; padding: 96px 32px 40px; border: 0; box-sizing: border-box; background: var(--bg); color: var(--fg); opacity: 0; transition: opacity .22s ease; overflow-y: auto; overscroll-behavior: contain; }
.site-menu-dialog::backdrop { background: var(--bg); }
.site-menu-dialog.is-open { opacity: 1; }
.site-menu-label { position: absolute; top: 28px; left: 32px; font-size: 22px; font-weight: 750; letter-spacing: -.04em; }
.site-menu-dialog .menu-content { display: grid; align-content: center; min-height: calc(100dvh - 176px); max-width: 1000px; margin: auto; }
.site-menu-dialog .site-nav { flex-direction: column; align-items: flex-start; gap: clamp(20px,4vh,38px); margin: 0; }
.site-menu-dialog .site-nav a { font-size: clamp(26px,5vw,64px); line-height: 1.2; letter-spacing: -.035em; white-space: normal; }
.site-menu-dialog .site-nav .site-learn { margin: 8px 0 0; font-size: 19px; letter-spacing: 0; padding: 8px 14px; }
.site-menu-dialog .site-nav .site-check { font-size: 18px; letter-spacing: 0; padding: 12px 20px; }
.menu-close span:first-child { transform: translateY(3.75px) rotate(45deg); }
.menu-close span:last-child { transform: translateY(-3.75px) rotate(-45deg); }
body.navigation-open { position: fixed; width: 100%; overflow: hidden; }
html { scrollbar-gutter: stable; }
@media (max-width: 1000px) {
  .site-header-inner { gap: 12px; padding-inline: 24px; }
  .site-nav { gap: 14px; margin-left: 12px; }
  .site-brand { font-size: 18px; }
  .site-nav a { font-size: 13px; }
  .site-nav .site-check { padding-inline: 12px; }
}
@media (max-width: 850px) {
  .site-header-inner { min-height: 76px; padding-inline: 20px; flex-wrap: wrap; }
  .navigation-ready .site-header-inner { padding-right: 76px; }
  .site-theme { margin-left: auto; }
  .navigation-ready .shared-header .site-nav { display: none; }
  .navigation-ready > .site-menu-control { display: flex; top: 15px; right: 18px; }
  .site-nav { flex: 1 0 100%; order: 3; flex-wrap: wrap; margin: 0; gap: 8px 16px; padding-bottom: 12px; }
  .site-nav .site-learn { margin-left: 0; }
  .site-menu-dialog .site-nav { padding: 0; }
  .site-signet { --signet-height: 30px; }
}
@media (prefers-reduced-motion: reduce) {
  .shared-header, .site-nav a, .site-menu-dialog { transition: none !important; }
}

.home-page:not(.navigation-ready) .site-header.shared-header { transform: none; opacity: 1; visibility: visible; pointer-events: auto; background: var(--bg) !important; border-bottom: 1px solid var(--border) !important; }