/* Navigation */
    .site-header {
      position: sticky; top: 0; z-index: 1000; height: 76px;
      background: rgba(255,255,255,.92); border-bottom: 1px solid rgba(219,229,235,.9); backdrop-filter: blur(16px);
    }
    .nav { height: 100%; display: flex; align-items: center; justify-content: space-between; gap: 30px; }
    .brand { display: inline-flex; align-items: center; gap: .7rem; color: var(--navy-950); font-size: 1.07rem; font-weight: 850; }
    .brand-mark {
      position: relative; display: grid; place-items: center; width: 37px; height: 37px;
      color: var(--white); background: linear-gradient(145deg, var(--blue-600), var(--cyan-400)); border-radius: 11px;
      box-shadow: 0 7px 18px rgba(8,120,200,.2);
    }
    .brand-mark svg { width: 22px; height: 22px; }
    .nav-links { display: flex; align-items: center; gap: clamp(16px, 2.2vw, 30px); margin-left: auto; }
    .nav-links a { color: var(--gray-700); font-size: .92rem; font-weight: 650; }
    .nav-links a:hover { color: var(--blue-600); }
    .menu-toggle { display: none; width: 44px; height: 44px; border: 0; border-radius: 10px; background: var(--gray-50); cursor: pointer; }
    .menu-toggle span { display: block; width: 20px; height: 2px; margin: 4px auto; background: var(--navy-900); transition: .2s; }