:root{
  --bg:#0b0f1a; --panel:#111827; --ink:#e5e7eb; --muted:#9aa4b2; --accent:#7c3aed; --border:#222733;
}
*{box-sizing:border-box}
html,body{margin:0;background:var(--bg);color:var(--ink);font-family:Inter,system-ui,-apple-system,Segoe UI,Roboto,Arial}
.container{max-width:1200px;margin:0 auto;padding:20px}
header{display:flex;align-items:center;justify-content:space-between;padding:12px 20px;border-bottom:1px solid rgba(255,255,255,.08);position:sticky;top:0;z-index:50;background:rgba(11,15,26,.65);backdrop-filter:blur(8px)}
header img{height:56px}
header nav{display:grid;grid-auto-flow:column;grid-auto-columns:max-content;gap:10px;overflow-x:auto;scroll-snap-type:x proximity}
header nav a{padding:10px 14px;border-radius:12px;text-decoration:none;color:var(--ink);font-weight:700;border:1px solid rgba(255,255,255,.08);background:rgba(17,24,39,.8)}
header nav a.active{background:linear-gradient(180deg,rgba(124,58,237,.25),rgba(124,58,237,.08));border-color:rgba(124,58,237,.55)}
main{padding:24px 20px}
.card{background:rgba(17,24,39,.85);border:1px solid rgba(255,255,255,.08);border-radius:14px;padding:16px;box-shadow:0 12px 30px rgba(0,0,0,.3);margin-bottom:16px}
.grid{display:grid;gap:16px}
.btn{appearance:none;border:0;border-radius:12px;background:var(--accent);color:#fff;padding:10px 14px;font-weight:800;cursor:pointer;text-decoration:none;display:inline-flex;align-items:center;gap:8px}
.btn.secondary{background:#1f2937}
footer{border-top:1px solid rgba(255,255,255,.08);padding:20px;color:var(--muted);text-align:center}
/* Profile flip */
.profile-wrap{display:grid;place-items:center}
.flip{position:relative;width:220px;height:220px;perspective:1000px}
.flip .inner{position:absolute;inset:0;transform-style:preserve-3d;transition:transform .6s}
.flip:hover .inner{transform:rotateY(180deg)}
.flip .face{position:absolute;inset:0;border-radius:999px;overflow:hidden;border:3px solid rgba(255,255,255,.08);box-shadow:0 10px 30px rgba(0,0,0,.35);backface-visibility:hidden}
.flip .back{transform:rotateY(180deg)}
.flip img{width:100%;height:100%;object-fit:cover}
.badge{display:inline-flex;align-items:center;gap:.4rem;font-size:12px;border-radius:999px;padding:6px 10px;background:#1f2937;border:1px solid #2b3547;color:#cbd5e1}
/* Quiz styles */
.opt{display:block;width:100%;text-align:left;margin:.5rem 0;padding:12px 14px;border-radius:12px;background:#0f172a;border:1px solid #2b3547;color:#fff;font-weight:800}
.opt.correct{background:#0b3d2b;border-color:#145c41}
.opt.wrong{background:#3d0b0b;border-color:#5e1111}
.chip{display:inline-flex;align-items:center;gap:.5rem;padding:6px 10px;border-radius:999px;border:1px solid rgba(255,255,255,.08);background:#111827;font-size:12px}
.chip.bad{background:#3d0b0b;border-color:#5e1111;color:#ffd0d0}
.chip.acc{background:#0b3d2b;border-color:#145c41;color:#c7ffde}
#timebar{height:6px;background:#7c3aed;border-radius:999px;width:100%}
.small{font-size:12px;color:#9aa4b2}
table{width:100%;border-collapse:separate;border-spacing:0 8px}
th,td{padding:10px 8px;text-align:left}
thead th{color:#cbd5e1;font-size:13px}
tbody tr{background:#111827;border:1px solid #2b3547}