:root{--bg:#0f1520;--panel:#182131;--panel2:#202d41;--text:#f4f7fb;--muted:#a8b5c8;--accent:#5ee1b2;--accent2:#6ca8ff;--bad:#ff7e8b;--line:#2d3b52}*{box-sizing:border-box}body{margin:0;background:linear-gradient(135deg,#0c111a,#152338);color:var(--text);font:15px/1.5 system-ui,-apple-system,Segoe UI,sans-serif}a{color:var(--accent2);text-decoration:none}.wrap{max-width:1200px;margin:auto;padding:24px}.top{display:flex;justify-content:space-between;align-items:center;border-bottom:1px solid var(--line);padding:12px 0 18px;margin-bottom:24px}.brand{font-size:22px;font-weight:800}.brand span{color:var(--accent)}nav{display:flex;gap:16px;align-items:center}.btn{border:0;border-radius:9px;padding:10px 15px;background:var(--accent2);color:#06101f;font-weight:700;cursor:pointer}.btn.secondary{background:var(--panel2);color:var(--text);border:1px solid var(--line)}.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(290px,1fr));gap:16px}.card{background:rgba(24,33,49,.95);border:1px solid var(--line);border-radius:14px;padding:18px}.card h2,.card h3{margin:0 0 8px}.muted{color:var(--muted)}.bar{height:8px;background:#0b1019;border-radius:5px;overflow:hidden;margin:10px 0}.bar i{display:block;height:100%;background:linear-gradient(90deg,var(--accent),var(--accent2))}.row{display:flex;justify-content:space-between;align-items:center;gap:12px;padding:11px 0;border-bottom:1px solid var(--line)}.row:last-child{border-bottom:0}.pill{font-size:12px;color:var(--muted)}.auth{max-width:440px;margin:10vh auto}.auth form{display:grid;gap:12px}.auth input,.quiz select{width:100%;padding:12px;border-radius:8px;border:1px solid var(--line);background:#0d1522;color:var(--text)}.error{color:var(--bad)}.success{color:var(--accent)}.stem{font-size:19px;white-space:pre-wrap;margin:18px 0}.choice{display:block;width:100%;text-align:left;margin:10px 0;padding:14px;border:1px solid var(--line);border-radius:10px;background:var(--panel);color:var(--text);cursor:pointer}.choice:hover,.choice.selected{border-color:var(--accent2);background:#263853}.choice.correct{border-color:var(--accent);background:#173b36}.choice.wrong{border-color:var(--bad);background:#3c2029}.explain{white-space:pre-wrap;background:#121b29;border-left:3px solid var(--accent);padding:14px;margin-top:18px}.hidden{display:none}.small{font-size:13px}.table{width:100%;border-collapse:collapse}.table th,.table td{text-align:left;padding:10px;border-bottom:1px solid var(--line)}