:root{
  --side:#07181c; --side-2:#0f2a2e; --side-active:#13383b; --side-line:#1d3a3e;
  --hero-1:#0b3330; --hero-2:#25554c;
  --ink:#0b1f22; --ink-2:#3d4f52; --muted:#6c7c7e;
  --accent:#1f7a5f; --mint:#d6f7e5; --mint-ink:#0b3d2e;
  --bg:#f5f5f0; --card:#ffffff; --line:#e5e7e1;
  --warn-bg:#fdebe2; --warn-ink:#a2401c;
  --radius:18px;
  --font:"Inter",system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;
}
*{box-sizing:border-box}
html,body{margin:0;height:100%}
body{font-family:var(--font);background:var(--bg);color:var(--ink);-webkit-font-smoothing:antialiased}
button{font-family:inherit;cursor:pointer}
a{color:inherit}

/* ---------- Layout ---------- */
.app{display:flex;min-height:100vh}
.sidebar{width:250px;flex:0 0 250px;background:var(--side);color:#fff;display:flex;flex-direction:column;
  padding:18px 10px 14px;position:sticky;top:0;height:100vh}
.brand{display:flex;align-items:center;gap:12px;padding:4px 8px 22px}
.brand-mark{width:44px;height:44px;border-radius:13px;border:1.5px solid rgba(255,255,255,.75);display:grid;place-items:center}
.brand-name{font-weight:800;font-size:17px;letter-spacing:-.02em}
.brand-tag{font-size:9.5px;font-weight:700;letter-spacing:.12em;color:#b8e8d0;margin-top:2px}
.workspace{margin:0 6px 18px;padding:12px 14px;border:1px solid var(--side-line);border-radius:14px;background:var(--side-2);
  color:#fff;text-align:left;width:calc(100% - 12px)}
.workspace b{display:block;font-size:13px;color:#d6f7e5}
.workspace span{font-size:13.5px;color:#c4d2d2}
.workspace small{display:block;margin-top:6px;font-size:11px;color:#7fb7a0}
.nav{display:flex;flex-direction:column;gap:3px}
.nav button{all:unset;cursor:pointer;padding:10px 13px;border-radius:10px;font-size:13.5px;font-weight:700;color:#e8efef}
.nav button:hover{background:var(--side-2)}
.nav button.active{background:var(--side-active)}
.nav button:focus-visible{outline:2px solid #6fd7a8}
.side-foot{margin-top:auto;border-top:1px solid var(--side-line);padding:12px 10px 0;display:flex;flex-direction:column;gap:12px}
.side-foot button{all:unset;cursor:pointer;font-size:12.5px;color:#c4d2d2;font-weight:500}
.side-foot button:hover{color:#fff}

.main{flex:1;min-width:0;display:flex;flex-direction:column}
.topbar{height:72px;background:#fff;border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;
  padding:0 34px;position:sticky;top:0;z-index:5}
.topbar h1{margin:0;font-size:15px;font-weight:700}
.topbar p{margin:2px 0 0;font-size:11.5px;color:var(--muted)}
.pill-user{border:1px solid var(--line);border-radius:999px;padding:8px 14px;font-size:12.5px;color:var(--ink-2);background:#fff;white-space:nowrap}
.menu-btn{display:none;background:none;border:0;font-size:22px;margin-right:10px;color:var(--ink)}
.content{padding:34px;max-width:1440px;width:100%}

/* ---------- Components ---------- */
.hero{position:relative;overflow:hidden;border-radius:var(--radius);padding:52px 42px 56px;color:#fff;
  background:radial-gradient(120% 140% at 85% 30%,var(--hero-2) 0%,var(--hero-1) 55%,#08292a 100%)}
.hero .big-letter{position:absolute;right:42px;top:50%;transform:translateY(-50%);font-size:130px;font-weight:900;color:rgba(255,255,255,.12);line-height:1}
.eyebrow{display:flex;align-items:center;gap:12px;font-size:11px;font-weight:800;letter-spacing:.18em;text-transform:uppercase;color:var(--accent)}
.eyebrow::before{content:"";width:22px;height:1.5px;background:currentColor}
.hero .eyebrow{color:#3fc28f}
.hero h2{margin:18px 0 0;font-size:clamp(34px,4.4vw,56px);font-weight:900;letter-spacing:-.045em;line-height:1.02;max-width:720px}
.hero p{margin:24px 0 0;font-size:16.5px;color:#d9e6e4;max-width:640px;line-height:1.5}

.stats{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,330px));gap:16px;margin:20px 0}
.stat{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:24px 22px}
.stat .label{font-size:13.5px;font-weight:700;color:var(--ink-2)}
.stat .value{font-size:24px;font-weight:800;margin:14px 0 12px;letter-spacing:-.01em}
.stat .value.xl{font-size:30px}
.stat .hint{font-size:11.5px;color:var(--muted)}

.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:34px 26px 18px;margin-bottom:20px}
.card.mint{background:#f2faf6;border-color:#cfeadc}
.card.dark{background:linear-gradient(100deg,#0b3330,#123f3a);color:#fff;border:0;display:flex;align-items:center;justify-content:space-between;gap:24px;padding:34px 26px}
.card.dark .eyebrow{color:#3fc28f}
.card.dark p{color:#d9e6e4;margin:10px 0 0;font-size:16px;line-height:1.55;max-width:680px}
.card-head{display:flex;align-items:flex-end;justify-content:space-between;gap:16px;padding-bottom:20px;border-bottom:1px solid var(--line)}
.card.dark .card-head,.card-head.flat{border:0;padding-bottom:0}
.card h3{margin:10px 0 0;font-size:24px;font-weight:800;letter-spacing:-.02em}
.link{background:none;border:0;color:var(--accent);font-weight:800;font-size:12.5px;padding:0}
.link.muted{color:var(--muted)}

.row{display:flex;align-items:center;gap:24px;padding:24px 0;border-bottom:1px solid var(--line)}
.row:last-child{border-bottom:0}
.row .meta{font-size:11px;font-weight:800;color:var(--accent);letter-spacing:.02em}
.row h4{margin:8px 0 6px;font-size:17px;font-weight:800}
.row p{margin:0;font-size:12.5px;color:var(--muted);line-height:1.6;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.row .grow{flex:1;min-width:0}
.row .status{width:150px;font-size:11.5px}
.row .status b{display:block;font-weight:800;color:var(--ink);margin-bottom:5px}
.row .status span{color:var(--muted)}
.row .actions{display:flex;flex-direction:column;gap:10px;min-width:180px}

.btn{border:0;border-radius:999px;padding:14px 26px;font-weight:800;font-size:13.5px;background:#06171a;color:#fff;white-space:nowrap}
.btn:hover{background:#163236}
.btn.mint{background:var(--mint);color:var(--mint-ink)}
.btn.mint:hover{background:#c3f1d8}
.btn.ghost{background:transparent;border:1px solid var(--line);color:var(--ink)}
.btn:disabled{opacity:.45;cursor:not-allowed}
.badge{display:inline-block;border-radius:999px;padding:6px 12px;font-size:11.5px;font-weight:800;background:var(--mint);color:var(--mint-ink)}
.badge.warn{background:var(--warn-bg);color:var(--warn-ink)}
.badge.grey{background:#eef0ec;color:var(--ink-2)}

.grid3{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:16px;padding-top:22px}
.course{border:1px solid var(--line);border-radius:16px;padding:24px 20px}
.course .meta{font-size:11px;font-weight:800;letter-spacing:.08em;color:var(--accent)}
.course h4{margin:10px 0 8px;font-size:18px;font-weight:800}
.course .sub{font-size:12px;color:var(--muted)}
.course .links{display:flex;gap:14px;margin-top:20px}

.progress{height:8px;background:#eef0ec;border-radius:99px;overflow:hidden;margin-top:14px}
.progress i{display:block;height:100%;background:var(--accent);border-radius:99px;transition:width .4s}

.notice{background:#e9f4ee;border-radius:12px;padding:14px 18px;font-size:13.5px;color:var(--ink-2);margin:20px 0 4px}
.notice b{color:var(--ink)}

.player-frame{position:relative;border-radius:16px;overflow:hidden;background:#06171a;margin-top:22px;height:min(78vh,820px)}
.player-frame iframe{width:100%;height:100%;border:0;background:#fff}
.player-actions{display:flex;gap:12px;flex-wrap:wrap}

table.grade{width:100%;border-collapse:collapse;font-size:13.5px;margin-top:8px}
.grade th{text-align:left;font-size:11px;letter-spacing:.1em;text-transform:uppercase;color:var(--muted);padding:14px 10px;border-bottom:1px solid var(--line)}
.grade td{padding:16px 10px;border-bottom:1px solid var(--line)}
.grade tr:last-child td{border-bottom:0}
.table-wrap{overflow-x:auto}
.empty{padding:30px 0;color:var(--muted);font-size:14px}

/* ---------- Modal ---------- */
.modal-back{position:fixed;inset:0;background:rgba(4,16,18,.55);display:grid;place-items:center;z-index:50;padding:16px}
.modal{background:#fff;border-radius:20px;padding:32px 28px;width:100%;max-width:440px}
.modal h3{margin:10px 0 6px;font-size:22px;font-weight:800}
.modal p{margin:0 0 20px;color:var(--muted);font-size:13.5px;line-height:1.5}
.modal label{display:block;font-size:12.5px;font-weight:700;margin:14px 0 6px}
.modal input{width:100%;padding:13px 14px;border:1px solid var(--line);border-radius:12px;font:inherit;font-size:14px}
.modal input:focus{outline:2px solid var(--accent);border-color:transparent}
.modal .btns{display:flex;gap:10px;justify-content:flex-end;margin-top:24px}
.modal .err{color:var(--warn-ink);font-size:12.5px;margin-top:10px;min-height:16px}
[hidden]{display:none!important}

/* ---------- Responsive ---------- */
@media (max-width:900px){
  .sidebar{position:fixed;left:0;top:0;z-index:40;transform:translateX(-100%);transition:transform .25s}
  .app.nav-open .sidebar{transform:none}
  .menu-btn{display:inline-block}
  .topbar{padding:0 16px}
  .content{padding:16px}
  .hero{padding:36px 22px 40px}
  .hero .big-letter{display:none}
  .row{flex-wrap:wrap}
  .row .status{width:auto}
  .row .actions{width:100%}
  .card.dark{flex-direction:column;align-items:flex-start}
  .stats{grid-template-columns:1fr}
  .player-frame{height:72vh}
}