/* ── Base ── */
  *, *::before, *::after { box-sizing: border-box; }
  html { scroll-behavior: smooth; scroll-padding-top: 80px; }
  body { margin: 0; -webkit-font-smoothing: antialiased; }
  img { display: block; max-width: 100%; }
  a { text-decoration: none; color: inherit; }
  button { cursor: pointer; border: none; background: none; font-family: inherit; }
  input, textarea, select { font-family: inherit; }

  /* ── Reveal animations ── */
  .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.visible {
    opacity: 1;
    transform: translateY(0);
  }
  .reveal.delay-1 { transition-delay: 0.1s; }
  .reveal.delay-2 { transition-delay: 0.2s; }
  .reveal.delay-3 { transition-delay: 0.3s; }

  /* ── Nav link hover underline ── */
  .nav-link {
    position: relative;
  }
  .nav-link::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 1px;
    background: currentColor;
    transition: width 0.3s ease;
  }
  .nav-link:hover::after {
    width: 100%;
  }

  /* ── Mobile menu ── */
  #mobile-menu.open {
    opacity: 1;
    pointer-events: all;
  }
  #mobile-menu.open .mobile-link {
    animation: fadeUp 0.3s ease forwards;
    opacity: 0;
  }
  #mobile-menu.open .mobile-link:nth-child(1) { animation-delay: 0.05s; }
  #mobile-menu.open .mobile-link:nth-child(2) { animation-delay: 0.1s; }
  #mobile-menu.open .mobile-link:nth-child(3) { animation-delay: 0.15s; }
  #mobile-menu.open .mobile-link:nth-child(4) { animation-delay: 0.2s; }
  #mobile-menu.open a:nth-child(5) { animation: fadeUp 0.3s ease forwards; opacity: 0; animation-delay: 0.25s; }

  @keyframes fadeUp {
    from { opacity: 0; transform: translateY(12px); }
    to { opacity: 1; transform: translateY(0); }
  }

  /* ── Hamburger animation ── */
  #menu-btn[aria-expanded="true"] .menu-line:nth-child(1) {
    transform: rotate(45deg) translate(3px, 3px);
  }
  #menu-btn[aria-expanded="true"] .menu-line:nth-child(2) {
    opacity: 0;
  }
  #menu-btn[aria-expanded="true"] .menu-line:nth-child(3) {
    transform: rotate(-45deg) translate(3px, -3px);
    width: 1.25rem;
  }

  /* ── Form focus styles ── */
  input:focus, textarea:focus {
    outline: none;
  }

  /* ── Selection color ── */
  ::selection {
    background: rgba(20, 184, 166, 0.15);
    color: inherit;
  }

  /* ── Smooth image loading ── */
  img {
    background-color: rgb(241 245 249);
  }

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

  /* ── Tablet and up adjustments ── */
  @media (min-width: 768px) {
    .reveal {
      transition-duration: 0.8s;
    }
  }