/* Estructura global: header, navegación y logo. */
header{position:sticky;top:0;z-index:10;background:rgba(5,8,22,.88);backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}
nav{display:flex;align-items:center;justify-content:space-between;height:68px}
.brand{display:flex;align-items:center;gap:10px;font-weight:800;font-size:18px}
.brand svg{width:34px;height:34px}
nav ul{display:flex;gap:28px;list-style:none;padding:0;font-size:15px;color:var(--gray)}
nav ul a:hover{color:#fff}