:root{
  --page:#eef8ff;
  --board:#4746b9;
  --board-deep:#39349c;
  --pink:#ef3d88;
  --blue:#687ce1;
  --paper:#ffffff;
  --ink:#26334d;
  --muted:#667085;
  --line:#e2e7f0;
  --download:#6d4fc2;
  --shadow:0 14px 32px rgba(39,43,105,.18);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;font-family:"Segoe UI",Arial,sans-serif;color:var(--ink);background:var(--page);line-height:1.55}
a{text-decoration:none;color:inherit}
.container{width:min(1080px,calc(100% - 30px));margin:auto}
header{background:#fff;border-bottom:1px solid var(--line)}
.nav{min-height:68px;display:flex;align-items:center;justify-content:space-between;gap:18px}
.brand{font-size:20px;font-weight:900;color:#17375e}
.brand span{display:inline-flex;margin-left:7px;padding:5px 9px;border-radius:999px;background:linear-gradient(135deg,#ff8a3d,#ee5f87);color:#fff;font-size:11px;letter-spacing:.05em}
.navlinks{display:flex;align-items:center;gap:7px;flex-wrap:wrap}
.navlinks a{font-weight:800;padding:8px 11px;border-radius:999px;background:#f7f5ff;color:#5d45a7}
.navlinks a.current{background:var(--download);color:#fff}
.page{padding:34px 0 64px}
.board{background:linear-gradient(160deg,var(--board),var(--board-deep));border-radius:28px;padding:38px clamp(18px,5vw,50px) 46px;box-shadow:var(--shadow)}
h1{text-align:center;color:#fff;font-size:clamp(34px,5vw,52px);margin:0 0 8px;letter-spacing:-.02em}
.intro{max-width:760px;margin:0 auto 30px;text-align:center;color:#e8eaff;font-size:17px}
.subjects{display:grid;gap:13px}
details{border-radius:18px;overflow:hidden;background:#fff}
summary{list-style:none;cursor:pointer}
summary::-webkit-details-marker{display:none}
.subject>summary{min-height:58px;padding:16px 24px;display:flex;align-items:center;justify-content:space-between;gap:16px;color:#fff;font-size:17px;font-weight:900;letter-spacing:.01em}
.subject:nth-child(odd)>summary{background:linear-gradient(90deg,var(--pink),#ed5596)}
.subject:nth-child(even)>summary{background:linear-gradient(90deg,#5e72d8,var(--blue))}
.plus{width:25px;height:25px;flex:0 0 25px;border:2px solid currentColor;border-radius:50%;display:grid;place-items:center;font-size:21px;line-height:1}
.plus::before{content:"+"}
details[open]>summary .plus::before{content:"−"}
.units{padding:13px;background:#f8f9ff;display:grid;gap:10px}
.unit{border:1px solid #dfe3f0;border-radius:14px;box-shadow:none}
.unit>summary{padding:13px 16px;display:flex;align-items:center;justify-content:space-between;gap:14px;color:#3c3a83;font-weight:900;background:#fff}
.unit .plus{width:22px;height:22px;flex-basis:22px;font-size:18px}
.topics{padding:4px 14px 12px;background:#fff}
.topic{padding:14px 0;border-bottom:1px solid var(--line)}
.topic:last-child{border-bottom:0}
.topic h3{font-size:16px;color:#3e4962;margin:0 0 8px}
.file{display:grid;grid-template-columns:minmax(0,1fr) auto;align-items:center;gap:18px;padding:10px 0}
.file+.file{border-top:1px dashed #e5e7ef}
.file-copy{min-width:0}
.file-title{font-size:17px;font-weight:900;color:#343181;text-decoration:underline;text-decoration-color:#c9c8ee;text-decoration-thickness:2px;text-underline-offset:4px}
.file p{margin:4px 0 0;color:var(--muted);font-size:14px}
.actions{display:flex;gap:8px;flex-wrap:wrap}
.btn{display:inline-flex;align-items:center;justify-content:center;min-height:40px;padding:8px 13px;border-radius:10px;font-weight:900;white-space:nowrap}
.view{background:#fff;color:#4b48a9;border:1px solid #cfd4e6}
.download{background:var(--download);color:#fff;border:1px solid var(--download)}
.btn:hover{transform:translateY(-1px)}
.empty{padding:18px;border-radius:12px;background:#fff;color:var(--muted);text-align:center;font-weight:700}
.status{display:inline-flex;margin-top:6px;padding:5px 9px;border-radius:999px;background:#fff4d6;color:#8b6300;font-size:13px;font-weight:900}
.note{margin-top:24px;padding:15px 18px;border-radius:15px;background:rgba(255,255,255,.14);color:#fff;text-align:center;font-weight:700}
footer{padding:0 0 34px;text-align:center;color:#5f6b80}
@media(max-width:780px){.nav{align-items:flex-start;padding:13px 0}.navlinks{justify-content:flex-end}.page{padding-top:18px}.board{border-radius:20px;padding:28px 14px 34px}.subject>summary{padding:15px 17px}.file{grid-template-columns:1fr}.actions{justify-content:flex-start}.btn{flex:1}}
@media(max-width:520px){.brand span{display:none}.navlinks a:not(.home):not(.current){display:none}}