/* ==========================================================================
   Responsive breakpoints — mobile-first
   ========================================================================== */

/* Tablet (≥ 640px) */
@media (min-width: 640px) {
  .grid-2 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .people-grid { grid-template-columns: repeat(2, 1fr); }
  .gallery-grid { grid-template-columns: repeat(3, 1fr); }
  .focus-list { grid-template-columns: repeat(2, 1fr); }
  .members-list { grid-template-columns: repeat(2, 1fr); }
  .overview-showcase { grid-template-columns: 1fr; }
}

/* Mobile nav close button (visible inside the open menu) */
/* Mobile Navigation Header Bar & Close Button */
@media (max-width: 959px) {
  .nav-header-bar {
    display: flex !important;
    align-items: center !important;
    justify-content: space-between !important;
    width: 100% !important;
    padding: 0.25rem 0.25rem 0.6rem 0.25rem !important;
    margin-bottom: 0.6rem !important;
    border-bottom: 1px solid rgba(10, 37, 64, 0.08) !important;
    flex-shrink: 0 !important;
  }
  .nav-header-title {
    font-family: var(--font-heading);
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--primary);
    display: flex;
    align-items: center;
    gap: 0.35rem;
    letter-spacing: 0.01em;
  }
  .nav-header-title span {
    background: var(--primary-soft);
    color: var(--primary);
    padding: 0.15rem 0.45rem;
    border-radius: 6px;
    font-size: 0.78rem;
    font-weight: 700;
  }
  .primary-nav .nav-close {
    position: static !important;
    width: 36px !important;
    height: 36px !important;
    display: flex !important;
    align-items: center !important;
    justify-content: center !important;
    background: rgba(10, 37, 64, 0.08) !important;
    border: 1px solid rgba(10, 37, 64, 0.12) !important;
    font-size: 24px !important;
    font-weight: 400 !important;
    line-height: 1 !important;
    color: var(--primary) !important;
    z-index: 160 !important;
    cursor: pointer !important;
    border-radius: 50% !important;
    transition: transform .18s var(--ease), background .18s var(--ease) !important;
    flex-shrink: 0 !important;
  }
  .primary-nav .nav-close:hover {
    background: rgba(10, 37, 64, 0.15) !important;
    transform: scale(1.08) !important;
  }
  .primary-nav .nav-close:focus-visible { outline: 2px solid var(--primary); outline-offset: 2px; }

  [data-theme="dark"] .nav-header-bar {
    border-bottom-color: rgba(255, 255, 255, 0.1) !important;
  }
  [data-theme="dark"] .nav-header-title {
    color: #F8FAFC !important;
  }
  [data-theme="dark"] .nav-header-title span {
    background: rgba(59, 130, 246, 0.2) !important;
    color: #60A5FA !important;
  }
  [data-theme="dark"] .primary-nav .nav-close {
    background: rgba(255, 255, 255, 0.12) !important;
    border-color: rgba(255, 255, 255, 0.2) !important;
    color: #F8FAFC !important;
  }
  [data-theme="dark"] .primary-nav .nav-close:hover {
    background: rgba(255, 255, 255, 0.22) !important;
  }
}

/* Desktop (≥ 960px) */
@media (min-width: 960px) {
  .grid-3 { grid-template-columns: repeat(3, 1fr); }
  .grid-4 { grid-template-columns: repeat(4, 1fr); }
  .people-grid { grid-template-columns: repeat(3, 1fr); }
  .gallery-grid { grid-template-columns: repeat(4, 1fr); }
  .focus-list { grid-template-columns: repeat(2, 1fr); }
  .members-list { grid-template-columns: repeat(2, 1fr); }
}

/* Large desktop (≥ 1200px) */
@media (min-width: 1200px) {
  .people-grid { grid-template-columns: repeat(4, 1fr); }
  .focus-list { grid-template-columns: repeat(3, 1fr); }
}

/* ---------- Mobile navigation drawer ---------- */
@media (max-width: 959px) {
  .site-header {
    z-index: 130;
  }
  .header-inner {
    min-height: 56px;
    padding: 0.35rem 0;
    position: relative;
  }
  .logo {
    flex: 1 1 auto;
    min-width: 0;
  }
  .logo-text strong { font-size: 0.95rem; }
  .logo-text small { display: none; }

  .nav-toggle {
    display: inline-flex !important;
    flex-shrink: 0;
    z-index: 101;
    background: rgba(10, 37, 64, 0.08);
    border: 1px solid rgba(10, 37, 64, 0.12);
    box-shadow: 0 4px 14px rgba(10, 37, 64, 0.08);
    width: 42px;
    height: 42px;
    border-radius: 12px;
  }
  .nav-toggle span {
    width: 4px;
    height: 4px;
    margin: 2px 0;
    border-radius: 50%;
    background: var(--primary);
    transition: opacity .24s ease, transform .24s ease;
  }
  .nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(0); }
  .nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0.4; }
  .nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(0); }

  [data-theme="dark"] .nav-toggle {
    background: rgba(255, 255, 255, 0.08) !important;
    border-color: rgba(255, 255, 255, 0.15) !important;
  }
  [data-theme="dark"] .nav-toggle span {
    background: #F8FAFC !important;
  }

  .primary-nav {
    position: fixed !important;
    top: 0 !important;
    left: 0 !important;
    right: 0 !important;
    bottom: 0 !important;
    display: flex !important;
    flex-direction: column !important;
    width: 100vw !important;
    max-width: 100vw !important;
    height: 100dvh !important;
    min-height: 100dvh !important;
    max-height: 100dvh !important;
    background: linear-gradient(180deg, rgba(255, 255, 255, 0.99) 0%, rgba(245, 249, 255, 0.99) 100%) !important;
    border: 0 !important;
    box-shadow: none !important;
    padding: 10px 12px 3rem 12px !important; /* Zero wasted empty space at the top */
    opacity: 0 !important;
    visibility: hidden !important;
    pointer-events: none !important;
    transform: translateY(-100%) !important;
    transition: transform .28s cubic-bezier(.2,.8,.2,1), opacity .24s ease, visibility .24s ease !important;
    overflow-y: auto !important;
    overflow-x: hidden !important;
    -webkit-overflow-scrolling: touch !important;
    z-index: 200 !important;
    overscroll-behavior: contain !important;
    box-sizing: border-box !important;
    overscroll-behavior-y: contain !important;
    backdrop-filter: blur(16px) saturate(1.2);
    -webkit-backdrop-filter: blur(16px) saturate(1.2);
  }

  [data-theme="dark"] .primary-nav {
    background: linear-gradient(180deg, rgba(11, 15, 23, 0.99) 0%, rgba(7, 11, 18, 0.99) 100%) !important;
  }

  .primary-nav.open {
    opacity: 1 !important;
    visibility: visible !important;
    pointer-events: auto !important;
    transform: translateY(0) !important;
  }
  .primary-nav:not(.open) {
    opacity: 0 !important;
    visibility: hidden !important;
    pointer-events: none !important;
    transform: translateY(-100%) !important;
  }

  .nav-backdrop {
    display: block;
    position: fixed;
    inset: 0 0 0 0;
    background: rgba(5, 16, 30, 0.45);
    z-index: 135;
    touch-action: none;
    opacity: 0;
    pointer-events: none;
    transition: opacity .24s ease;
  }
  .nav-backdrop.open {
    opacity: 1;
    pointer-events: auto;
  }

  /* Grid showing ALL 12 navigation items directly */
  .nav-list {
    display: grid !important;
    grid-template-columns: repeat(2, minmax(0, 1fr)) !important;
    gap: 0.5rem !important;
    padding: 0 0 2.5rem 0 !important;
    width: 100% !important;
    flex: 1 1 auto !important;
    margin: 0 !important;
    list-style: none !important;
  }

  .nav-list > .nav-item {
    display: flex !important;
    width: 100% !important;
  }

  /* Flatten dropdown so all 5 sub-links are directly visible */
  .nav-list > .nav-item.has-dropdown {
    display: contents !important;
  }
  .nav-list > .nav-item.has-dropdown > .nav-link {
    display: none !important; /* Hide the generic 'More' trigger */
  }
  .nav-list > .nav-item.has-dropdown .dropdown {
    display: contents !important;
    max-height: none !important;
    visibility: visible !important;
    opacity: 1 !important;
    overflow: visible !important;
    padding: 0 !important;
    margin: 0 !important;
    border: 0 !important;
    box-shadow: none !important;
    background: transparent !important;
  }
  .nav-list > .nav-item.has-dropdown .dropdown li {
    display: flex !important;
    width: 100% !important;
  }

  /* Clean, compact, accessible card buttons for all links */
  .nav-list a {
    display: flex !important;
    align-items: center !important;
    justify-content: center !important;
    padding: 0.6rem 0.5rem !important;
    font-size: 0.88rem !important;
    font-weight: 600 !important;
    width: 100% !important;
    text-align: center !important;
    min-height: 46px !important;
    border-radius: 10px !important;
    background: rgba(255, 255, 255, 0.95) !important;
    border: 1px solid rgba(10, 37, 64, 0.1) !important;
    box-shadow: 0 2px 6px rgba(10, 37, 64, 0.04) !important;
    color: var(--primary) !important;
    text-decoration: none !important;
    transition: transform .15s ease, background .15s ease, color .15s ease, border-color .15s ease !important;
  }

  .nav-list a:hover {
    background: var(--primary-soft) !important;
    color: var(--primary) !important;
    transform: translateY(-1px) !important;
  }

  .nav-list a.active {
    background: var(--primary) !important;
    color: #FFFFFF !important;
    border-color: var(--primary) !important;
    box-shadow: 0 4px 12px rgba(10, 37, 64, 0.2) !important;
  }

  [data-theme="dark"] .nav-list a {
    background: rgba(23, 34, 54, 0.95) !important;
    border-color: rgba(255, 255, 255, 0.08) !important;
    color: #F8FAFC !important;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.4) !important;
  }

  [data-theme="dark"] .nav-list a:hover {
    background: #1E293B !important;
    color: #60A5FA !important;
    border-color: #60A5FA !important;
  }

  [data-theme="dark"] .nav-list a.active {
    background: #3B82F6 !important;
    color: #FFFFFF !important;
    border-color: #3B82F6 !important;
    box-shadow: 0 4px 14px rgba(59, 130, 246, 0.4) !important;
  }

  /* Single column on very narrow mobile screens */
  @media (max-width: 359px) {
    .nav-list {
      grid-template-columns: 1fr !important;
    }
  }

  /* Logo text adjustments */
  .logo-text strong { font-size: 1rem; }
  .logo-text small { font-size: 0.62rem; }
}

/* ---------- Tablet+ header tweaks ---------- */
@media (min-width: 960px) {
  .nav-backdrop { display: none !important; }
}

/* ---------- Stats bar responsive ---------- */
@media (max-width: 639px) {
  .stats-bar {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-3);
    margin-top: 0;
    padding: var(--space-4);
  }
  .stat-number { font-size: 1.5rem; }
  .stat-label { font-size: 0.72rem; line-height: 1.4; }
  .pi-spotlight-right {
    grid-template-columns: 1fr;
  }
  .pi-spotlight-right .pi-spotlight-content {
    order: 2;
  }
  .pi-spotlight-right .pi-spotlight-media {
    order: 1;
  }
  .pi-spotlight-left {
    grid-template-columns: 1fr;
  }
  .pi-spotlight-left .pi-spotlight-media {
    order: 1;
  }
  .pi-spotlight-left .pi-spotlight-content {
    order: 2;
  }
  .person-card {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    text-align: left;
    gap: var(--space-3);
  }
  .person-photo {
    width: 100%;
    max-width: 180px;
    height: auto;
    aspect-ratio: 1 / 1;
    margin: 0 0 var(--space-3);
  }
  .person-card h4,
  .person-role,
  .badge {
    width: 100%;
  }
  .alumni-layout {
    grid-template-columns: 1fr;
  }
  .alumni-media {
    align-items: flex-start;
  }
  .alumni-content p {
    font-size: 0.94rem;
    line-height: 1.7;
  }
  .labs-preview { grid-template-columns: 1fr; }
  .pi-profile { grid-template-columns: 1fr; text-align: center; }
  .pi-photo { margin: 0 auto; max-width: 200px; }
  .pi-contact { justify-content: center; }
  .pi-spotlight,
  .pi-spotlight-left,
  .pi-spotlight-right {
    grid-template-columns: 1fr;
    gap: var(--space-4);
  }
  .pi-spotlight-media {
    max-width: min(100%, 280px);
    width: 100%;
    margin: 0 auto;
  }
  .page-banner {
    min-height: 260px;
    padding: var(--space-7) 0 var(--space-6);
  }
  .join-hero-card {
    flex-direction: column;
    align-items: flex-start;
  }
  .join-hero-actions { width: 100%; justify-content: flex-start; }
  .join-form-callout { flex-direction: column; align-items: flex-start; }
  .overview-theme-grid { grid-template-columns: 1fr; }
  .overview-theme-card { grid-template-columns: 1fr; text-align: center; justify-items: center; }
  .overview-theme-card img { width: 100%; max-width: 100px; height: 100px; }
  .page-banner h1 {
    font-size: clamp(1.8rem, 5vw, 2.4rem);
  }
  .contact-grid { grid-template-columns: 1fr; }
  .map-embed-content { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: var(--space-5); }
  .footer-bottom { flex-direction: column; text-align: center; }
  .org-branch { grid-template-columns: 1fr; }
  .org-branch::before { display: none; }
  .org-node { min-width: 0; width: 100%; }
}

/* ---------- Small mobile ---------- */
@media (max-width: 480px) {
  .container { padding: 0 var(--space-4); }
  .section { padding: var(--space-6) 0; }
  .header-inner { min-height: 60px; }
  .hero { padding: var(--space-7) 0 var(--space-6); }
  .hero-inner { max-width: 100%; }
  .hero-actions { flex-direction: column; align-items: stretch; }
  .hero-actions .btn { justify-content: center; }
  .page-banner { min-height: 230px; padding: var(--space-6) 0; }
  .page-banner h1 { font-size: 1.8rem; }
  .filter-bar { flex-direction: column; align-items: stretch; }
  .filter-bar input[type="search"], .filter-bar select { min-width: 0; width: 100%; }
  .lightbox-prev { left: var(--space-2); }
  .lightbox-next { right: var(--space-2); }
}

/* ---------- Reduced motion ---------- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  .reveal { opacity: 1; transform: none; }
}