/* YOLO Academic — Mobile nav + small-screen polish (additive) */
.nav-burger{display:none;align-items:center;justify-content:center;width:42px;height:40px;border-radius:999px;border:1px solid var(--line);background:#fff;color:var(--text);cursor:pointer;box-shadow:0 8px 18px rgba(17,24,39,.06);position:relative;flex:0 0 auto;}
.nav-burger span{display:block;width:18px;height:2px;background:currentColor;border-radius:2px;position:relative;}
.nav-burger span::before,.nav-burger span::after{content:"";position:absolute;left:0;width:18px;height:2px;background:currentColor;border-radius:2px;}
.nav-burger span::before{top:-6px;}
.nav-burger span::after{top:6px;}
body.nav-open .nav-burger span{background:transparent;}
body.nav-open .nav-burger span::before{top:0;transform:rotate(45deg);}
body.nav-open .nav-burger span::after{top:0;transform:rotate(-45deg);}

.nav-overlay{position:fixed;inset:0;background:rgba(15,23,42,.35);opacity:0;pointer-events:none;transition:opacity .2s ease;z-index:40;}
body.nav-open .nav-overlay{opacity:1;pointer-events:auto;}

@media (max-width:920px){
  .nav-inner{padding:10px 12px;}
  .brand-sub{display:none;}
  .tabs{display:none !important;}
  .nav-burger{display:inline-flex;}
  body.nav-open .tabs{
    display:flex !important;
    position:fixed;
    top:64px;
    left:12px;
    right:12px;
    z-index:50;
    flex-direction:column;
    gap:8px;
    padding:10px;
    background:rgba(255,255,255,.96);
    backdrop-filter:blur(10px);
    border:1px solid rgba(15,23,42,.10);
    border-radius:16px;
    box-shadow:0 18px 40px rgba(17,24,39,.18);
  }
  body.nav-open .tab{width:100%;text-align:center;justify-content:center;}
  .nav-right{gap:8px;flex-wrap:nowrap;}
  .lang-toggle{padding:8px 12px 8px 40px;}
}

@media (max-width:560px){
  .brand-name{font-size:14px;}
  .brand .logo{width:30px;height:30px;border-radius:10px;}
  .hero-actions{flex-direction:column;align-items:flex-start;}
  .hero-actions .btn{width:100%;justify-content:center;}
}