/* ===== BASE ===== */
  *, *::before, *::after { box-sizing: border-box; }
  html { scroll-behavior: smooth; scroll-padding-top: 64px; }
  body { margin: 0; -webkit-font-smoothing: antialiased; -moz-osx-font-smoothing: grayscale; }
  img { display: block; max-width: 100%; }
  ::selection { background: #99f6e4; color: #042f2e; }

  /* ===== NAV LINKS ===== */
  .nav-link { position: relative; }
  .nav-link::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 1px;
    background: #0d9488;
    transition: width 0.25s ease;
  }
  .nav-link:hover::after { width: 100%; }

  /* ===== MOBILE MENU ===== */
  #mobile-menu.open { opacity: 1; pointer-events: all; }
  #mobile-menu.closed { opacity: 0; pointer-events: none; }
  .mobile-nav-link { transition: opacity 0.2s, transform 0.2s; }
  #mobile-menu.open .mobile-nav-link { opacity: 1; transform: translateY(0); }
  #mobile-menu.closed .mobile-nav-link { opacity: 0; transform: translateY(8px); }

  /* stagger mobile links */
  #mobile-menu.open .mobile-nav-link:nth-child(1) { transition-delay: 0.05s; }
  #mobile-menu.open .mobile-nav-link:nth-child(2) { transition-delay: 0.1s; }
  #mobile-menu.open .mobile-nav-link:nth-child(3) { transition-delay: 0.15s; }
  #mobile-menu.open .mobile-nav-link:nth-child(4) { transition-delay: 0.2s; }
  #mobile-menu.open .mobile-nav-link:nth-child(5) { transition-delay: 0.25s; }

  /* hamburger animation */
  #menu-btn[aria-expanded="true"] .menu-line:nth-child(1) { transform: translateY(5px) rotate(45deg); }
  #menu-btn[aria-expanded="true"] .menu-line:nth-child(2) { opacity: 0; }
  #menu-btn[aria-expanded="true"] .menu-line:nth-child(3) { transform: translateY(-5px) rotate(-45deg); width: 5rem; }

  /* ===== REVEAL ANIMATIONS ===== */
  .reveal {
    opacity: 1;
    transform: translateY(0);
    transition: opacity 0.6s ease, transform 0.6s ease;
  }

  @media (prefers-reduced-motion: no-preference) {
    .reveal {
      opacity: 0;
      transform: translateY(20px);
      transition: opacity 0.7s cubic-bezier(0.22, 1, 0.36, 1), transform 0.7s cubic-bezier(0.22, 1, 0.36, 1);
    }
    .reveal.revealed {
      opacity: 1;
      transform: translateY(0);
    }
  }

  /* ===== FOCUS ===== */
  :focus-visible { outline: 2px solid #14b8a6; outline-offset: 2px; border-radius: 4px; }

  /* ===== SCROLLBAR ===== */
  ::-webkit-scrollbar { width: 6px; }
  ::-webkit-scrollbar-track { background: #f8fafc; }
  ::-webkit-scrollbar-thumb { background: #cbd5e1; border-radius: 3px; }
  ::-webkit-scrollbar-thumb:hover { background: #94a3b8; }