/* NAV */
  nav { 
    position:fixed; top:0; left:0; width:100%; padding:10px 0 18px; 
    background:rgba(15,15,15,0.55); 
    backdrop-filter:blur(18px);
    -webkit-backdrop-filter: blur(18px);
    z-index:999; 
    border-radius:0 0 24px 24px;
    box-shadow:0 18px 45px rgba(0,0,0,0.6);
    border-bottom:1px solid rgba(255,255,255,0.08);
  }
  body.light nav{ 
    background:rgba(255,255,255,0.7);
    border-bottom:1px solid rgba(0,0,0,0.06);
    box-shadow:0 18px 45px rgba(0,0,0,0.12);
  }
  nav ul{ list-style:none; display:flex; justify-content:center; gap:40px; }
  nav a{ 
    text-decoration:none; color:inherit; font-size:18px; font-weight:500; position:relative;
    padding:6px 10px;
    border-radius:999px;
  }
  nav a::after{ 
    content:""; width:0%; height:2px; background:#48c6ef; position:absolute; bottom:-4px; left:16px; transition:0.3s; 
  }
  nav a:hover{ 
    background:rgba(255,255,255,0.04);
  }
  nav a:hover::after{ width:60%; }