/* Wide navigation: solid text over a neutral surface with 10% opacity. */
.motion-prototype .site-header {
  --navigation-surface-rgb: 210 210 210;
  --navigation-surface-opacity: .1;
  --navigation-menu-rgb: 242 242 242;
  --navigation-switch-surface: #fafafa;
  --navigation-text: #4d4d4d;
  --navigation-active: #171717;
  --navigation-subdued: #939393;
  position: sticky;
  z-index: 30;
  top: 16px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr);
  align-items: center;
  gap: 16px;
  width: calc(100% - 48px);
  max-width: none;
  min-height: 52px;
  margin: 16px auto 8px;
  padding: 4px 24px;
  border: 0;
  border-radius: 32px;
  color: var(--navigation-active);
  background: transparent;
  box-shadow: none;
  isolation: isolate;
  transform: translateY(0);
  transition: transform var(--motion-duration-panel,240ms) var(--motion-ease-standard,cubic-bezier(.2,.7,.2,1));
}
.motion-prototype .site-header[data-navigation-hidden="true"] {
  transform: translateY(calc(-100% - 32px));
  pointer-events: none;
}
.motion-prototype .site-header::before {
  content: '';
  position: absolute;
  z-index: -1;
  inset: 0;
  border-radius: inherit;
  background: rgb(var(--navigation-surface-rgb) / var(--navigation-surface-opacity));
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  pointer-events: none;
}
.motion-prototype[data-view="stage"] .site-header { position: fixed; inset: 16px 0 auto; margin: 0 auto; }
:root[data-reading-mode="study"] .motion-prototype:not(:has(.scene-work[data-tone="dark"])) .site-header,
.motion-prototype:has(.scene-work[data-tone="light"]) .site-header {
  --navigation-surface-rgb: 80 80 80;
  --navigation-menu-rgb: 38 38 38;
  --navigation-switch-surface: #292929;
  --navigation-text: #ccc;
  --navigation-active: #fff;
  --navigation-subdued: #818181;
}
.motion-prototype .site-header .brand { display: flex; align-items: center; justify-self: start; min-width: 0; min-height: 44px; margin: 0; font-size: 18px; line-height: 1; letter-spacing: .02em; font-weight: 500; }
.motion-prototype .site-header .brand-mark { display:block; width:104px; aspect-ratio:253.054 / 37.1159; background:currentColor; mask:url('/seadon-logo.svg') center / contain no-repeat; -webkit-mask:url('/seadon-logo.svg') center / contain no-repeat; transition:opacity var(--motion-duration-panel,240ms) var(--motion-ease-standard,cubic-bezier(.2,.7,.2,1)); }
.motion-prototype .site-header .main-nav { display: flex; align-items: center; align-self: center; justify-self: center; justify-content: center; gap: 0; margin: 0; }
.motion-prototype .site-header .main-nav a { min-height: 44px; padding: 0 14px; border-radius: 22px; color: var(--navigation-text); background: transparent; font-size: var(--theme-nav-size); font-weight: var(--theme-nav-weight); line-height: 1.4; letter-spacing: 0; transition: color var(--motion-duration-feedback,120ms) var(--motion-ease-standard,cubic-bezier(.2,.7,.2,1)), background-color var(--motion-duration-state,180ms) var(--motion-ease-standard,cubic-bezier(.2,.7,.2,1)); }
.motion-prototype .site-header .main-nav a::after { content: none; }
.motion-prototype .site-header .main-nav a[aria-current] { color: var(--navigation-active); }
.motion-prototype .navigation-actions { display: flex; align-items: center; justify-self: end; gap: 8px; margin: 0; }
.motion-prototype .reading-mode-toggle,
.motion-prototype .navigation-menu-toggle {
  position: relative;
  display: grid;
  place-items: center;
  flex-shrink: 0;
  width: 44px;
  height: 44px;
  min-width: 44px;
  min-height: 44px;
  padding: 0;
  border: 0;
  border-radius: 50%;
  color: var(--navigation-active);
  background: transparent;
  box-shadow:none;
  transition: color var(--motion-duration-feedback,120ms) var(--motion-ease-standard,cubic-bezier(.2,.7,.2,1));
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}
/* A single two-tone disc keeps the reading-mode control quiet at header scale. */
.motion-prototype .reading-mode-orbit { display:block; width:24px; height:24px; fill:none; stroke:currentColor; stroke-width:1.2; pointer-events:none; transform:rotate(0); transition:transform var(--motion-duration-panel,240ms) var(--motion-ease-standard,cubic-bezier(.2,.7,.2,1)); }
.motion-prototype .reading-mode-half { fill:currentColor; stroke:none; transform-origin:12px 12px; transition:transform var(--motion-duration-state,180ms) var(--motion-ease-standard,cubic-bezier(.2,.7,.2,1)); }
.motion-prototype .reading-mode-toggle[aria-pressed="true"] .reading-mode-half { transform:rotate(180deg); }
.motion-prototype .navigation-menu-toggle { display: none; }
.motion-prototype .skip { position: fixed; z-index: 40; }
.motion-prototype #content,
.motion-prototype .about-body > section,
.motion-prototype .detail-body [id] { scroll-margin-top: 108px; }
.motion-prototype .site-header :is(a, button):focus-visible { outline: 2px solid var(--navigation-active); outline-offset: 3px; }
@media (max-width: 1023px) {
  .motion-prototype .site-header .main-nav a { padding-inline: 12px; }
}
@media (max-width: 767px) {
  .motion-prototype .site-header { grid-template-columns: minmax(0, 1fr) auto; gap: 12px; top: 16px; width: calc(100% - 32px); min-height: 52px; margin-top: 16px; padding: 4px 16px; }
  .motion-prototype .site-header .brand { min-width: 0; font-size: 16px; }
  .motion-prototype .site-header .main-nav { position: absolute; inset: calc(100% + 8px) 0 auto; display: grid; grid-template-columns: 1fr; gap: 0; justify-self: stretch; width: auto; margin: 0; padding: 8px; border: 0; border-radius: 24px; background: rgb(var(--navigation-menu-rgb) / .9); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px); box-shadow: 0 4px 16px rgb(0 0 0 / 6%); visibility: hidden; opacity: 0; transform: translateY(calc(-1 * var(--motion-distance-panel,4px))); pointer-events: none; transition: opacity var(--motion-duration-state,180ms) var(--motion-ease-standard,cubic-bezier(.2,.7,.2,1)), transform var(--motion-duration-state,180ms) var(--motion-ease-standard,cubic-bezier(.2,.7,.2,1)), visibility 0s var(--motion-duration-state,180ms); }
  .motion-prototype .site-header[data-menu-open="true"] .main-nav { visibility: visible; opacity: 1; transform: translateY(0); pointer-events: auto; transition-duration: var(--motion-duration-panel,240ms), var(--motion-duration-panel,240ms), 0s; transition-delay: 0s; }
  .motion-prototype .site-header .main-nav a { min-height: 52px; padding: 12px 16px; border: 0; border-radius: 16px; font-size: 15px; }
  .motion-prototype .navigation-actions { gap: 4px; }
  .motion-prototype .navigation-menu-toggle { display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 5px; }
  .motion-prototype .navigation-menu-toggle span { width: 16px; height: 1px; background: currentColor; transition: transform var(--motion-duration-state,180ms) var(--motion-ease-standard,cubic-bezier(.2,.7,.2,1)); }
  .motion-prototype .navigation-menu-toggle[aria-expanded="true"] span:first-child { transform: translateY(3px) rotate(45deg); }
  .motion-prototype .navigation-menu-toggle[aria-expanded="true"] span:last-child { transform: translateY(-3px) rotate(-45deg); }
  .motion-prototype #content,
  .motion-prototype .about-body > section,
  .motion-prototype .detail-body [id] { scroll-margin-top: 100px; }
}
@media (hover: hover) and (pointer: fine) {
  .motion-prototype .reading-mode-toggle:hover .reading-mode-orbit { transform:rotate(24deg); }
  .motion-prototype .site-header .brand:hover .brand-mark { opacity:.6; }
  .motion-prototype .site-header .main-nav:has(a:hover) a:not(:hover) { color: var(--navigation-subdued); }
  .motion-prototype .site-header .main-nav a:hover { color: var(--navigation-active); }
}
@media (prefers-reduced-motion: reduce) {
  .motion-prototype .site-header,
  .motion-prototype .navigation-actions button,
  .motion-prototype .site-header .brand-mark,
  .motion-prototype .reading-mode-orbit,
  .motion-prototype .reading-mode-half,
  .motion-prototype .site-header .main-nav,
  .motion-prototype .site-header .main-nav a,
  .motion-prototype .navigation-menu-toggle span { transition: none; }
  .motion-prototype .reading-mode-toggle:hover .reading-mode-orbit { transform:none; }
}