/* Liquid Glass mobile UI — header, nav menu, floating tab bar.
   Scoped to phone-size screens (≤780px), matches the existing mobile breakpoint. */

.glass-tabbar {
  display: none;
}

@media (max-width: 780px) {
  /* ---- Floating bottom tab bar ---- */
  .glass-tabbar {
    display: flex;
    position: fixed;
    left: 12px;
    right: 12px;
    bottom: calc(12px + env(safe-area-inset-bottom));
    z-index: 40;
    border-radius: 999px;
    padding: 6px;
    text-decoration: none;
  }

  .glass-tabbar__indicator {
    position: absolute;
    top: 6px;
    left: 6px;
    width: calc((100% - 12px) / 3);
    height: calc(100% - 12px);
    border-radius: 999px;
    background: var(--color-white);
    box-shadow: 0 4px 14px rgba(0, 0, 0, 0.25);
    opacity: 0;
    transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.2s ease;
  }

  .glass-tabbar:has(.is-active) .glass-tabbar__indicator {
    opacity: 1;
  }

  .glass-tabbar:has(.glass-tabbar__item:nth-child(3).is-active) .glass-tabbar__indicator {
    transform: translateX(100%);
  }

  .glass-tabbar:has(.glass-tabbar__item:nth-child(4).is-active) .glass-tabbar__indicator {
    transform: translateX(200%);
  }

  .glass-tabbar__item {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 3px;
    padding: 10px 0;
    border-radius: 999px;
    color: var(--color-white);
    font-weight: 700;
    font-size: 0.75rem;
    text-decoration: none;
    position: relative;
    z-index: 1;
    transition: color 0.25s ease;
  }

  .glass-tabbar__item.is-active {
    color: var(--color-red);
  }

  .glass-tabbar__icon {
    width: 22px;
    height: 22px;
    flex-shrink: 0;
  }

  /* Hide the floating tab bar while the mobile nav menu is open */
  .main-header:has(#site-nav.is-open) ~ .glass-tabbar {
    display: none;
  }

  /* Room for the floating tab bar so it never covers footer content */
  body {
    padding-bottom: calc(88px + env(safe-area-inset-bottom));
  }

  /* ---- Floating nav menu becomes a detached glass card ---- */
  .site-nav.is-open {
    left: 12px;
    right: 12px;
    top: calc(100% + 8px);
    border-radius: 20px;
    padding: 0.5rem;
  }

  .site-nav.is-open ul li a {
    border-bottom: none;
    border-radius: 12px;
    padding: 0.85rem 1rem;
  }

  .site-nav.is-open ul li a:hover,
  .site-nav.is-open ul li a:active {
    background: rgba(255, 255, 255, 0.4);
  }

  /* ---- Glass surfaces (with backdrop-filter) ---- */
  @supports (backdrop-filter: blur(1px)) or (-webkit-backdrop-filter: blur(1px)) {
    .main-header {
      background: rgba(255, 255, 255, 0.55);
      -webkit-backdrop-filter: blur(18px) saturate(160%);
      backdrop-filter: blur(18px) saturate(160%);
      border-bottom: 1px solid rgba(255, 255, 255, 0.6);
      box-shadow: 0 8px 32px rgba(6, 23, 44, 0.12);
    }

    .site-nav.is-open {
      background: rgba(255, 255, 255, 0.45);
      -webkit-backdrop-filter: blur(20px) saturate(180%);
      backdrop-filter: blur(20px) saturate(180%);
      border: 1px solid rgba(255, 255, 255, 0.7);
      box-shadow: 0 12px 40px rgba(6, 23, 44, 0.25), inset 0 1px 0 rgba(255, 255, 255, 0.8);
    }

    .glass-tabbar {
      background: rgba(3, 26, 54, 0.55);
      -webkit-backdrop-filter: blur(18px) saturate(180%);
      backdrop-filter: blur(18px) saturate(180%);
      border: 1px solid rgba(255, 255, 255, 0.15);
      box-shadow: 0 10px 30px rgba(0, 0, 0, 0.35), inset 0 1px 0 rgba(255, 255, 255, 0.1);
    }
  }

  /* ---- Fallback: opaque surfaces when backdrop-filter is unsupported ---- */
  @supports not ((backdrop-filter: blur(1px)) or (-webkit-backdrop-filter: blur(1px))) {
    .main-header {
      background: var(--color-white);
    }

    .site-nav.is-open {
      background: var(--color-white);
    }

    .glass-tabbar {
      background: var(--color-navy);
    }
  }
}