/* ── Base ── */
  *, *::before, *::after { box-sizing: border-box; }
  html { scroll-behavior: smooth; scroll-padding-top: 80px; }
  body { overflow-x: hidden; }
  img { max-width: 100%; height: auto; }

  /* ── Selection ── */
  ::selection { background: #0F766E; color: #fff; }

  /* ── Scrollbar ── */
  ::-webkit-scrollbar { width: 6px; }
  ::-webkit-scrollbar-track { background: #f8fafc; }
  ::-webkit-scrollbar-thumb { background: #94a3b8; border-radius: 3px; }
  ::-webkit-scrollbar-thumb:hover { background: #0F766E; }

  /* ── Navbar ── */
  #navbar {
    background: rgba(248, 250, 252, 0.85);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid rgba(226, 232, 240, 0.5);
  }
  #navbar.scrolled {
    background: rgba(255, 255, 255, 0.95);
    box-shadow: 0 1px 20px rgba(0, 0, 0, 0.06);
  }

  /* ── Service cards ── */
  .service-card {
    position: relative;
    overflow: hidden;
  }
  .service-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0;
    width: 100%; height: 3px;
    background: linear-gradient(90deg, #0F766E, #2dd4bf);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.5s cubic-bezier(0.22, 1, 0.36, 1);
  }
  .service-card:hover::before {
    transform: scaleX(1);
  }

  /* ── Hero image stack animation ── */
  @media (prefers-reduced-motion: no-preference) {
    .hero-image-main {
      animation: heroFloat 6s ease-in-out infinite;
    }
    .hero-image-secondary {
      animation: heroFloatSecondary 8s ease-in-out infinite;
    }
    @keyframes heroFloat {
      0%, 100% { transform: translateY(0); }
      50% { transform: translateY(-8px); }
    }
    @keyframes heroFloatSecondary {
      0%, 100% { transform: translateY(0); }
      50% { transform: translateY(6px); }
    }
  }

  /* ── Scroll reveal (progressive enhancement) ── */
  @media (prefers-reduced-motion: no-preference) {
    .reveal {
      opacity: 0;
      transform: translateY(24px);
      transition: opacity 0.8s cubic-bezier(0.22, 1, 0.36, 1),
                  transform 0.8s cubic-bezier(0.22, 1, 0.36, 1);
    }
    .reveal.revealed {
      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; }
  }

  /* ── Button focus ── */
  button:focus-visible,
  a:focus-visible,
  input:focus-visible,
  select:focus-visible,
  textarea:focus-visible {
    outline: 2px solid #0F766E;
    outline-offset: 2px;
  }

  /* ── Mobile menu transition ── */
  #mobile-menu {
    animation: slideDown 0.3s cubic-bezier(0.22, 1, 0.36, 1);
  }
  @keyframes slideDown {
    from { opacity: 0; transform: translateY(-8px); }
    to { opacity: 1; transform: translateY(0); }
  }