/* ==========================================================================
   responsive.css — mobile-first breakpoints: 600px, 900px, 1200px
   ========================================================================== */

/* --------------------------------------------------------------------------
   ≥ 600px — small tablets
   -------------------------------------------------------------------------- */
@media (min-width: 600px) {
  .grid--2,
  .grid--3,
  .grid--4 {
    grid-template-columns: repeat(2, 1fr);
  }

  .hero {
    min-height: 70vh;
  }
}

/* --------------------------------------------------------------------------
   ≥ 900px — desktop: inline nav with mega-menu, horizontal timeline
   -------------------------------------------------------------------------- */
@media (min-width: 900px) {
  .grid--3,
  .grid--4 {
    grid-template-columns: repeat(3, 1fr);
  }

  .two-col {
    grid-template-columns: 1fr 1fr;
  }

  /* Nav becomes inline; hide hamburger */
  .nav-toggle {
    display: none;
  }

  .site-nav {
    position: static;
    width: auto;
    padding: 0;
    background: transparent;
    border: none;
    box-shadow: none;
    transform: none;
    overflow: visible;
  }

  .site-nav__list {
    flex-direction: row;
    align-items: center;
    gap: 0;
  }

  .site-nav__item {
    position: relative;
  }

  .site-nav__link {
    padding: var(--space-sm) 0.7rem;
    white-space: nowrap;
  }

  .site-nav__link[aria-current="page"] {
    border-left: none;
    border-bottom: 3px solid var(--color-secondary);
    border-radius: 0;
    background: transparent;
  }

  /* Mega-menu dropdown */
  .site-nav__sub {
    position: absolute;
    top: 100%;
    left: 0;
    z-index: 100;
    min-width: 14rem;
    padding: var(--space-sm);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transform: translateY(0.5rem);
    transition: opacity var(--transition-fast), transform var(--transition-fast),
      visibility var(--transition-fast);
  }

  .site-nav__item:hover > .site-nav__sub,
  .site-nav__item:focus-within > .site-nav__sub {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }

  .site-nav__sub-link {
    font-size: var(--fs-base);
    padding: var(--space-sm) var(--space-md);
  }

  /* Timeline: horizontal scroll strip */
  .timeline--horizontal {
    display: flex;
    gap: var(--space-lg);
    overflow-x: auto;
    padding: var(--space-lg) var(--space-sm) var(--space-md);
    scroll-snap-type: x mandatory;
  }

  .timeline--horizontal::before {
    top: 0.35rem;
    bottom: auto;
    left: 0;
    right: 0;
    width: auto;
    height: 3px;
  }

  .timeline--horizontal .timeline__item {
    flex: 0 0 20rem;
    margin-bottom: 0;
    scroll-snap-align: start;
  }

  .timeline--horizontal .timeline__item::before {
    left: 0;
    top: -1.35rem;
  }

  .gallery__grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* --------------------------------------------------------------------------
   ≥ 1200px — wide desktop
   -------------------------------------------------------------------------- */
@media (min-width: 1200px) {
  .grid--4 {
    grid-template-columns: repeat(4, 1fr);
  }

  .gallery__grid {
    grid-template-columns: repeat(4, 1fr);
  }

  .hero {
    min-height: 78vh;
  }

  .site-nav__link {
    padding-inline: var(--space-md);
  }
}