:root{
  --bg:#f7f6f2; --card:#ffffff; --ink:#1b2430; --muted:#5c6773;
  --line:#e3dfd6; --accent:#0b2a4a; --gold:#c8a24b;
  --ok:#0f766e; --bad:#b91c1c; --radius:14px;
  --shadow:0 1px 2px rgba(20,25,35,.06), 0 8px 24px rgba(20,25,35,.06);
}
*{box-sizing:border-box}
html,body{margin:0;padding:0}
body{
  background:var(--bg); color:var(--ink);
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  font-size:16px; line-height:1.55; -webkit-font-smoothing:antialiased;
}
a{color:#12467a}
.topbar{
  position:sticky; top:0; z-index:20;
  display:flex; flex-wrap:wrap; gap:10px; align-items:center; justify-content:space-between;
  padding:12px 18px; background:rgba(11,42,74,.97); color:#fff; backdrop-filter:blur(8px);
}
.brand{display:flex; align-items:center; gap:10px; font-weight:700; letter-spacing:.2px}
.brand small{font-weight:400; opacity:.65; margin-left:6px}
.dot{width:10px;height:10px;border-radius:50%;background:var(--gold);display:inline-block}
.tabs{display:flex; gap:4px; flex-wrap:wrap}
.tabs button{
  background:transparent; color:#dfe6ef; border:1px solid transparent;
  padding:7px 12px; border-radius:999px; cursor:pointer; font:inherit; font-size:14px;
}
.tabs button:hover{background:rgba(255,255,255,.08)}
.tabs button.active{background:var(--gold); color:#1b2430; font-weight:600}
.wrap{max-width:1080px; margin:0 auto; padding:22px 18px 70px}

h1{font-size:26px; margin:6px 0 4px}
h2{font-size:21px; margin:26px 0 8px}
h3{font-size:17px; margin:18px 0 6px}
p{margin:8px 0}
ul,ol{margin:8px 0 8px 22px; padding:0}
li{margin:4px 0}
hr{border:0;border-top:1px solid var(--line);margin:22px 0}
blockquote{margin:12px 0;padding:10px 14px;border-left:3px solid var(--gold);background:#fffdf6;border-radius:0 10px 10px 0;color:#3d4653}
code{background:#eef0f3;padding:1px 5px;border-radius:5px;font-size:.92em}
table{border-collapse:collapse;width:100%;margin:12px 0;background:#fff;border-radius:10px;overflow:hidden;font-size:14.5px}
th,td{border-bottom:1px solid var(--line);padding:8px 10px;text-align:left;vertical-align:top}
th{background:#eef1f5;font-weight:600}

.grid{display:grid;gap:14px}
.g2{grid-template-columns:repeat(auto-fit,minmax(300px,1fr))}
.g3{grid-template-columns:repeat(auto-fit,minmax(230px,1fr))}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:16px;box-shadow:var(--shadow)}
.course-card{cursor:pointer;transition:transform .12s ease, box-shadow .12s ease;position:relative;overflow:hidden}
.course-card:hover{transform:translateY(-2px)}
.course-card .bar{position:absolute;left:0;top:0;bottom:0;width:5px}
.course-card h3{margin:0 0 2px;font-size:17px}
.course-card .meta{color:var(--muted);font-size:13px}
.course-card .stats{display:flex;gap:10px;flex-wrap:wrap;margin-top:10px;font-size:12.5px;color:var(--muted)}
.pill{background:#eef1f5;border-radius:999px;padding:3px 9px}
.pill.ok{background:#e7f3f0;color:#0f5f56}

.btn{
  display:inline-flex;align-items:center;gap:8px;justify-content:center;
  background:var(--accent); color:#fff; border:0; border-radius:10px;
  padding:11px 16px; font:inherit; font-weight:600; cursor:pointer;
}
.btn:hover{filter:brightness(1.08)}
.btn.ghost{background:#fff;color:var(--accent);border:1px solid var(--line)}
.btn.gold{background:var(--gold);color:#1b2430}
.btn:disabled{opacity:.5;cursor:not-allowed}
.btn.sm{padding:7px 12px;font-size:14px}

.row{display:flex;gap:10px;align-items:center;flex-wrap:wrap}
.spread{justify-content:space-between}
.muted{color:var(--muted)}
.small{font-size:13px}
.center{text-align:center}
.hide{display:none !important}

.crumbs{margin-bottom:14px;font-size:14px;color:var(--muted)}
.crumbs a{cursor:pointer;text-decoration:none;color:#12467a}

.reader{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:26px 28px;box-shadow:var(--shadow)}
.reader h1{font-size:24px;border-bottom:2px solid var(--gold);padding-bottom:8px}
.reader h2{font-size:19px;margin-top:28px;color:#0b2a4a}
.reader h3{font-size:16px;color:#22354a}
.reader table{font-size:14px}
@media(max-width:640px){.reader{padding:18px 16px}}

.quizbox{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:20px;box-shadow:var(--shadow)}
.progress{height:8px;background:#e9e5dc;border-radius:999px;overflow:hidden;margin:6px 0 16px}
.progress > i{display:block;height:100%;background:var(--gold);transition:width .25s ease}
.qtext{font-size:19px;font-weight:600;line-height:1.45;margin:6px 0 16px}
.options{display:grid;gap:9px}
.opt{
  display:flex;gap:10px;align-items:flex-start;
  background:#fbfaf7;border:1px solid var(--line);border-radius:11px;padding:11px 13px;
  cursor:pointer;font:inherit;text-align:left;width:100%;
}
.opt:hover{border-color:#c9c2b3;background:#fff}
.opt .k{font-weight:700;color:#8a6d2f;min-width:18px}
.opt.sel{border-color:var(--accent);background:#eef2f7}
.opt.correct{border-color:var(--ok);background:#e7f3f0}
.opt.wrong{border-color:var(--bad);background:#fdecec}
.feedback{margin-top:14px;padding:12px 14px;border-radius:11px;font-size:14.5px}
.feedback.ok{background:#e7f3f0;color:#0b4f49;border:1px solid #bfe0da}
.feedback.bad{background:#fdecec;color:#7f1d1d;border:1px solid #f3c7c7}
.feedback .ans{display:block;margin-top:6px;font-weight:600}

.input{
  width:100%;padding:12px 14px;border:1px solid var(--line);border-radius:10px;font:inherit;background:#fbfaf7;
}
.input:focus{outline:2px solid #cfd8e3;background:#fff}

.flash{
  background:#fff;border:1px solid var(--line);border-radius:18px;box-shadow:var(--shadow);
  min-height:260px;display:flex;flex-direction:column;justify-content:center;align-items:center;
  padding:26px;text-align:center;cursor:pointer;user-select:none;
}
.flash .front{font-size:22px;font-weight:700}
.flash .back{font-size:17px;color:#2c3947;margin-top:14px}
.flash .hint{font-size:12px;color:var(--muted);margin-top:18px}

.stat{display:flex;gap:18px;flex-wrap:wrap;margin:10px 0 2px}
.stat div{font-size:13px;color:var(--muted)}
.stat b{display:block;font-size:20px;color:var(--ink)}

.notes-list{display:grid;gap:8px;margin-top:10px}
.note{display:flex;justify-content:space-between;gap:12px;align-items:center;background:#fff;border:1px solid var(--line);border-radius:10px;padding:10px 12px;font-size:14px}
.note a{font-weight:600;text-decoration:none}
.note .kb{color:var(--muted);font-size:12px;white-space:nowrap}

.toast{
  position:fixed;left:50%;bottom:26px;transform:translateX(-50%) translateY(20px);
  background:#1b2430;color:#fff;padding:10px 16px;border-radius:10px;font-size:14px;
  opacity:0;pointer-events:none;transition:.25s ease;z-index:50;
}
.toast.show{opacity:1;transform:translateX(-50%) translateY(0)}

.badge{display:inline-block;background:#eef1f5;color:#334155;border-radius:8px;padding:3px 8px;font-size:12px;font-weight:600}
.empty{padding:30px;text-align:center;color:var(--muted)}