/* ── Base & Utilities ── */
  *, *::before, *::after { box-sizing: border-box; }
  html { scroll-behavior: smooth; scroll-padding-top: 80px; }
  body { margin: 0; }

  /* ── Scroll Reveal (progressive enhancement) ── */
  @media (prefers-reduced-motion: no-preference) {
    .reveal {
      opacity: 0;
      transform: translateY(24px);
      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);
    }
  }
  @media (prefers-reduced-motion: reduce) {
    .reveal { opacity: 1; transform: none; }
  }

  /* ── Navbar ── */
  #navbar {
    background: transparent;
    transition: background 0.3s ease, box-shadow 0.3s ease, padding 0.3s ease;
  }
  #navbar.scrolled {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(12px);
    box-shadow: 0 1px 0 rgba(0, 0, 0, 0.06);
  }
  #navbar.scrolled .font-serif { color: #0f172a; }
  #navbar.scrolled .nav-link { color: #475569; }
  #navbar.scrolled .nav-link:hover { color: #0d9488; background: #f0fdfa; }

  /* ── Mobile Menu ── */
  #mobile-menu {
    animation: slideDown 0.25s cubic-bezier(0.22, 1, 0.36, 1);
  }
  @keyframes slideDown {
    from { opacity: 0; transform: translateY(-8px); }
    to { opacity: 1; transform: translateY(0); }
  }

  /* ── Smooth anchor offsets for fixed header ── */
  section[id] {
    scroll-margin-top: 80px;
  }

  /* ── Selection Color ── */
  ::selection {
    background: rgba(13, 148, 136, 0.2);
    color: #0f172a;
  }