/* ===== HEADER ===== */
  .site-header-wrap{position:fixed;top:0;left:0;right:0;z-index:100;}
  .announcement-bar{
    position:relative;overflow:hidden;
    background:linear-gradient(90deg,#2a3f8f,#3b4fd8);
    color:#fff;text-align:center;
    font-size:13px;font-weight:600;letter-spacing:.01em;
    max-height:50px;transition:max-height .35s ease, padding .35s ease, opacity .3s ease;
    padding:11px 46px;
  }
  .announcement-bar.collapsed{max-height:0;padding-top:0;padding-bottom:0;opacity:0;}
  .announcement-bar .ann-inner{
    display:flex;align-items:center;justify-content:center;gap:10px;flex-wrap:wrap;
  }
  .announcement-bar .ann-ic{font-size:14px;}
  .announcement-bar .ann-sep{opacity:.5;}
  .announcement-bar a.ann-link{
    color:#fff;font-weight:700;text-decoration:underline;text-underline-offset:2px;
    display:inline-flex;align-items:center;gap:4px;
  }
  .announcement-close{
    position:absolute;right:14px;top:50%;transform:translateY(-50%);
    width:24px;height:24px;border-radius:50%;border:none;background:rgba(255,255,255,.15);
    color:#fff;font-size:15px;line-height:1;cursor:pointer;
    display:flex;align-items:center;justify-content:center;
    transition:background .2s ease;
  }
  .announcement-close:hover{background:rgba(255,255,255,.28);}
  header{
    position:relative;
    isolation:isolate;
    background:transparent;
    border-bottom:1px solid transparent;
    transition:border-color .4s ease;
  }
  /* Liquid Glass: a translucent, colour-picking surface with a luminous rim and soft specular sheen.
     The header stays completely blended into the hero until the existing scroll threshold is crossed. */
  header::before{
    content:"";
    position:absolute;
    inset:0;
    z-index:-1;
    pointer-events:none;
    opacity:0;
    background:
      radial-gradient(ellipse at 14% 0%,rgba(91,133,255,.10),transparent 48%),
      radial-gradient(ellipse at 84% 0%,rgba(158,119,255,.08),transparent 44%),
      linear-gradient(180deg,rgba(28,37,67,.38) 0%,rgba(13,18,39,.68) 100%);
    -webkit-backdrop-filter:blur(24px) saturate(155%);
    backdrop-filter:blur(24px) saturate(155%);
    box-shadow:inset 0 1px 0 rgba(255,255,255,.19),inset 0 -1px 0 rgba(255,255,255,.07),0 8px 24px rgba(0,0,0,.10);
    transition:opacity .38s ease;
  }
  header.scrolled{
    border-bottom-color:rgba(255,255,255,.12);
  }
  header.scrolled::before{opacity:1;}
  @supports not ((backdrop-filter:blur(1px)) or (-webkit-backdrop-filter:blur(1px))){
    header.scrolled::before{
      background:linear-gradient(180deg,rgba(22,29,54,.96),rgba(13,18,39,.97));
    }
  }
  @media (prefers-reduced-transparency:reduce){
    header.scrolled::before{
      -webkit-backdrop-filter:none;
      backdrop-filter:none;
      background:rgba(13,18,39,.96);
    }
  }
  .nav{
    display:flex;align-items:center;justify-content:space-between;
    padding:18px var(--pad-x);max-width:1280px;margin:0 auto;color:#fff;
  }
  .logo{font-size:22px;font-weight:800;color:#fff;letter-spacing:.3px;}
  .logo span{color:var(--blue2);}
  .logo .dot{color:var(--pink);}
  .nav-links{display:flex;gap:34px;align-items:center;}
  .nav-links a{font-size:14.5px;font-weight:500;color:#cfd3e8;transition:color .2s;}
  .nav-links a:hover{color:#fff;}
  .nav-dropdown{position:relative;}
  .nav-dropdown summary{
    display:flex;align-items:center;gap:7px;list-style:none;cursor:pointer;
    color:#cfd3e8;font-size:14.5px;font-weight:500;transition:color .2s;
  }
  .nav-dropdown summary::-webkit-details-marker{display:none;}
  .nav-dropdown summary::after{
    content:"";display:inline-block;width:6px;height:6px;flex:0 0 6px;margin: -3px 1px 0;
    border-right:1.5px solid currentColor;border-bottom:1.5px solid currentColor;
    transform:rotate(45deg);transition:transform .2s ease,margin .2s ease;
  }
  .nav-dropdown[open] summary::after{transform:rotate(225deg);margin-top:3px;}
  .nav-dropdown summary:hover,.nav-dropdown summary:focus-visible{color:#fff;}
  .nav-submenu{
    position:absolute;top:calc(100% + 14px);left:-14px;min-width:210px;
    display:flex;flex-direction:column;gap:3px;padding:8px;
    border:1px solid rgba(255,255,255,.16);border-radius:15px;
    background:rgba(13,18,39,.96);box-shadow:0 14px 36px rgba(0,0,0,.35);
    -webkit-backdrop-filter:blur(16px);backdrop-filter:blur(16px);
  }
  .nav-submenu a{display:block;padding:9px 11px;border-radius:9px;color:#e5e9ff;font-size:14px;}
  .nav-submenu a:hover,.nav-submenu a:focus-visible{background:rgba(255,255,255,.08);}
  .nav-dropdown-courses .nav-submenu{min-width:248px;padding:9px;gap:6px;}
  .nav-course-group+.nav-course-group{border-top:1px solid rgba(255,255,255,.1);padding-top:6px;}
  .nav-submenu a.nav-batch-link{font-weight:800;color:#fff;padding:8px 11px 5px;}
  .nav-course-links{margin:0 0 2px 11px;padding-left:8px;border-left:1px solid rgba(139,166,255,.28);}
  .nav-submenu .nav-course-links a{padding:7px 10px;font-size:13px;color:#cfd7f4;}
  @property --course-glow-angle{
    syntax:"<angle>";inherits:false;initial-value:0deg;
  }
  .course-card.course-highlight{z-index:3;}
  .course-card.course-highlight::after{
    content:"";position:absolute;z-index:5;inset:0;border-radius:inherit;padding:7px;
    background:conic-gradient(from var(--course-glow-angle),
      transparent 0deg 274deg,rgba(67,184,255,.16) 290deg,#4bbdff 305deg,
      #a4edff 319deg,#fff 328deg,#d7a0ff 340deg,#a453ff 350deg,
      transparent 360deg);
    -webkit-mask:linear-gradient(#000 0 0) content-box,linear-gradient(#000 0 0);
    -webkit-mask-composite:xor;mask-composite:exclude;
    filter:drop-shadow(0 0 7px rgba(105,199,255,.95))
      drop-shadow(0 0 17px rgba(105,145,255,.8))
      drop-shadow(0 0 30px rgba(173,101,255,.58));
    pointer-events:none;animation:courseEdgeSweep 2.2s linear infinite;
  }
  @keyframes courseEdgeSweep{to{--course-glow-angle:360deg;}}
  @media(prefers-reduced-motion:reduce){
    .course-card.course-highlight::after{animation-duration:.01ms;}
  }
  .nav-right{display:flex;align-items:center;gap:14px;}
  .icon-btn{
    width:38px;height:38px;border-radius:50%;
    border:1.5px solid rgba(255,255,255,.2);
    display:flex;align-items:center;justify-content:center;
    color:#fff;background:transparent;cursor:pointer;
  }