.student-nav{display:none}
@media(max-width:639px){
  body{padding-bottom:84px}
  .student-nav{position:fixed;left:12px;right:12px;bottom:12px;z-index:100;display:grid;grid-template-columns:repeat(3,1fr);padding:6px 6px max(6px,env(safe-area-inset-bottom));border:1px solid rgba(255,255,255,.32);border-radius:18px;background:rgba(20,16,42,.94);box-shadow:0 12px 30px rgba(0,0,0,.28);backdrop-filter:blur(14px)}
  .student-nav a{display:flex;min-height:48px;align-items:center;justify-content:center;border-radius:12px;color:#fff;text-decoration:none;font:700 .82rem/1 system-ui,sans-serif}
  .student-nav a:focus-visible{outline:3px solid #ffd166;outline-offset:1px}
  .student-nav a:first-child{background:#2fd27a;color:#071c11}
}