:root{--bg:#0b1020;--bg-soft:#121a33;--card:#161f3d;--card-2:#1c274d;--border:#27325c;--text:#e7ecff;--muted:#9aa6d4;--primary:#61dafb;--primary-2:#4fa8d8;--accent:#7c5cff;--green:#3ddc97;--red:#ff6b81;--amber:#fc6;--radius:14px;--mono:"SF Mono","JetBrains Mono","Fira Code",Menlo,Consolas,monospace}*{box-sizing:border-box}body,html{margin:0;padding:0;background:radial-gradient(1200px 600px at 80% -10%,#1b2750 0,transparent 60%),radial-gradient(900px 500px at -10% 10%,#1a1538 0,transparent 55%),var(--bg);color:var(--text);font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica,Arial,sans-serif;-webkit-font-smoothing:antialiased;min-height:100vh}.container{max-width:860px;margin:0 auto;padding:32px 20px 80px}.brand{display:flex;align-items:center;gap:12px;margin-bottom:8px}.brand .logo{font-size:30px;filter:drop-shadow(0 0 14px rgba(97,218,251,.5))}.brand h1{font-size:22px;margin:0;letter-spacing:.2px}.brand .sub{color:var(--muted);font-size:13px;margin-top:2px}.hero{background:linear-gradient(160deg,var(--card) 0,var(--bg-soft) 100%);border:1px solid var(--border);border-radius:var(--radius);padding:36px 28px;text-align:center;margin-top:28px}.hero h2{margin:0 0 8px;font-size:26px}.hero p{color:var(--muted);margin:0 auto 24px;max-width:520px;line-height:1.6}.stats{display:flex;gap:14px;justify-content:center;margin:0 0 26px;flex-wrap:wrap}.stat{background:var(--card-2);border:1px solid var(--border);border-radius:12px;padding:12px 18px;min-width:96px}.stat .n{font-size:22px;font-weight:700;color:var(--primary)}.stat .l{font-size:12px;color:var(--muted)}.track-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));grid-gap:16px;gap:16px;margin-top:8px}.track-card{display:flex;flex-direction:column;align-items:flex-start;gap:6px;text-align:left;cursor:pointer;background:var(--card-2);border:1px solid var(--border);border-radius:var(--radius);padding:22px 20px;color:var(--text);transition:transform .1s ease,border-color .15s ease,box-shadow .2s ease}.track-card:hover{transform:translateY(-2px);border-color:var(--primary);box-shadow:0 10px 30px rgba(0,0,0,.35)}.track-icon{font-size:34px}.track-name{font-size:18px;font-weight:700}.track-blurb{font-size:13px;color:var(--muted);line-height:1.45}.track-count{margin-top:6px;font-size:12.5px;font-weight:600;color:var(--primary)}.results-track{font-size:14px;color:var(--muted);margin-bottom:8px;text-transform:capitalize}.setup-head{display:flex;align-items:center;gap:14px;margin-bottom:24px}.setup-section{margin-bottom:22px}.setup-label{font-size:14px;font-weight:600;margin-bottom:10px}.segmented{display:flex;flex-wrap:wrap;gap:8px}.seg{display:flex;flex-direction:column;align-items:center;gap:2px;cursor:pointer;background:var(--card-2);border:1px solid var(--border);color:var(--text);border-radius:10px;padding:10px 16px;font-size:14px;font-weight:600;min-width:64px;transition:border-color .15s ease,background .15s ease,transform .08s ease}.seg:hover:not(:disabled){border-color:var(--primary-2)}.seg.active{border-color:var(--primary);background:#1a2a52;color:var(--primary)}.seg:disabled{opacity:.35;cursor:not-allowed}.seg-sub{font-size:10.5px;font-weight:500;color:var(--muted);text-transform:none}.seg.active .seg-sub{color:var(--primary-2)}.btn{-webkit-appearance:none;-moz-appearance:none;appearance:none;border:none;cursor:pointer;border-radius:10px;padding:12px 22px;font-size:15px;font-weight:600;transition:transform .08s ease,box-shadow .2s ease,background .2s ease;color:#07101f;background:linear-gradient(180deg,var(--primary) 0,var(--primary-2) 100%);box-shadow:0 6px 22px rgba(97,218,251,.28)}.btn:hover{transform:translateY(-1px)}.btn:active{transform:translateY(0)}.btn:disabled{opacity:.5;cursor:not-allowed;transform:none}.btn.secondary{background:var(--card-2);color:var(--text)}.btn.ghost,.btn.secondary{border:1px solid var(--border);box-shadow:none}.btn.ghost{background:transparent;color:var(--muted)}.topbar{display:flex;align-items:center;justify-content:space-between;margin:24px 0 14px;gap:16px}.progress-wrap{flex:1 1;height:8px;background:var(--card-2);border-radius:99px;overflow:hidden;border:1px solid var(--border)}.progress-bar{height:100%;background:linear-gradient(90deg,var(--accent),var(--primary));transition:width .3s ease}.qcount{font-size:13px;color:var(--muted);white-space:nowrap}.qcard{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:24px}.qmeta{display:flex;gap:8px;margin-bottom:14px;flex-wrap:wrap}.tag{font-size:11px;text-transform:uppercase;letter-spacing:.6px;padding:4px 10px;border-radius:99px;border:1px solid var(--border);color:var(--muted);background:var(--bg-soft)}.tag.diff-junior{color:var(--green);border-color:rgba(61,220,151,.4)}.tag.diff-mid{color:var(--amber);border-color:rgba(255,204,102,.4)}.tag.diff-senior{color:var(--red);border-color:rgba(255,107,129,.4)}.tag.type{color:var(--primary);border-color:rgba(97,218,251,.4)}.qprompt{font-size:19px;line-height:1.5;margin:0 0 20px}.options{display:flex;flex-direction:column;gap:10px}.option{text-align:left;background:var(--card-2);border:1px solid var(--border);color:var(--text);border-radius:10px;padding:14px 16px;cursor:pointer;font-size:15px;display:flex;gap:12px;align-items:flex-start;transition:border-color .15s ease,background .15s ease}.option:hover:not(:disabled){border-color:var(--primary-2)}.option .letter{font-weight:700;color:var(--muted);min-width:18px}.option.selected{border-color:var(--primary);background:#1a2a52}.option.correct{border-color:var(--green);background:rgba(61,220,151,.12)}.option.wrong{border-color:var(--red);background:rgba(255,107,129,.12)}.option:disabled{cursor:default}.code-area{width:100%;min-height:220px;background:#0a0f22;color:#d6e2ff;border:1px solid var(--border);border-radius:10px;padding:14px 16px;font-family:var(--mono);font-size:13.5px;line-height:1.6;resize:vertical;-moz-tab-size:2;tab-size:2}.code-area:focus{outline:none;border-color:var(--primary-2)}.hint{font-size:12.5px;color:var(--muted);margin:8px 2px 0}.feedback{margin-top:18px;border-radius:10px;padding:14px 16px;font-size:14px;line-height:1.55;border:1px solid var(--border)}.feedback.ok{background:rgba(61,220,151,.1);border-color:rgba(61,220,151,.4)}.feedback.no{background:rgba(255,107,129,.1);border-color:rgba(255,107,129,.4)}.feedback .head{font-weight:700;margin-bottom:6px}.feedback pre{background:#0a0f22;border:1px solid var(--border);border-radius:8px;padding:12px;overflow-x:auto;font-family:var(--mono);font-size:12.5px;margin:10px 0 0;color:#cfe}.actions{display:flex;gap:12px;margin-top:22px;justify-content:flex-end;flex-wrap:wrap}.results{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:32px 28px;text-align:center}.score-ring{font-size:52px;font-weight:800;background:linear-gradient(90deg,var(--primary),var(--accent));-webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent}.review-item{text-align:left;border-top:1px solid var(--border);padding:14px 4px;font-size:14px}.review-item .q{font-weight:600;margin-bottom:4px}.review-item .mark.ok{color:var(--green)}.review-item .mark.no{color:var(--red)}.footer-note{margin-top:28px;text-align:center;color:var(--muted);font-size:12.5px}.footer-note code{font-family:var(--mono);background:var(--card-2);padding:2px 6px;border-radius:6px}