:root{--ink:#26344a;--muted:#6d7c8f;--cream:#fffaf0;--peach:#ffd5b8;--mint:#c9f3df;--yellow:#ffe58a;--purple:#8874e8;--line:#d9dfe8}*{box-sizing:border-box}body{margin:0;min-height:100vh;color:var(--ink);font-family:"Microsoft YaHei","PingFang SC",sans-serif;background:radial-gradient(circle at 10% 10%,#fff 0 8%,transparent 9%),linear-gradient(135deg,#d8f3ff,#fff6cf 52%,#d9f8e4);background-size:34px 34px,auto}.app{width:min(840px,calc(100% - 28px));margin:auto;padding:32px 0 24px}.hero{display:flex;gap:18px;align-items:center;margin-bottom:20px}.mascot{display:grid;place-items:center;width:76px;height:76px;border:4px solid var(--ink);border-radius:28px;background:var(--peach);font-size:44px;box-shadow:0 6px 0 var(--ink);transform:rotate(-4deg)}h1{margin:0;font-size:clamp(32px,7vw,56px);letter-spacing:-2px}.eyebrow{margin:0 0 4px;color:#8b5b3e;font-weight:900;font-size:13px}.intro{margin:5px 0 0;color:var(--muted);font-size:16px}.panel{padding:25px;border:3px solid var(--ink);border-radius:28px;background:rgba(255,255,255,.9);box-shadow:0 9px 0 var(--ink)}h2{margin:0 0 18px;font-size:25px}.levels{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}.level{display:flex;flex-direction:column;align-items:flex-start;gap:5px;padding:16px;border:2px solid var(--line);border-radius:18px;background:#fff;color:var(--ink);text-align:left;cursor:pointer;transition:.18s}.level span{font-size:27px}.level strong{font-size:16px}.level small{color:var(--muted);font-size:12px;line-height:1.4}.level.active{border-color:var(--purple);background:#f1efff;box-shadow:inset 0 -4px 0 #d8d2ff}.primary,.secondary{border:3px solid var(--ink);border-radius:15px;font:inherit;font-weight:900;cursor:pointer}.primary{display:block;width:100%;margin-top:20px;padding:14px;background:var(--yellow);color:var(--ink);box-shadow:0 5px 0 var(--ink);font-size:18px}.primary:active,.secondary:active,.answers button:active{transform:translateY(3px);box-shadow:none}.primary span{margin-left:8px}.secondary{display:block;margin:17px auto 0;padding:10px 18px;background:#fff;color:var(--ink);font-size:14px}.hidden{display:none}.status{display:flex;justify-content:space-between;font-weight:900;color:#5c6c80;font-size:14px}.progress{height:10px;margin:10px 0 20px;overflow:hidden;border-radius:99px;background:#e9edf2}.progress div{height:100%;width:0;background:linear-gradient(90deg,#72d9ac,#8874e8);transition:.25s}.lab-card{padding:22px;border:2px dashed #abb6c7;border-radius:20px;background:var(--cream)}.question-head{display:flex;justify-content:space-between;gap:12px;align-items:center}.tag{padding:6px 10px;border-radius:99px;background:var(--mint);font-size:12px;font-weight:900}.hint{color:var(--muted);font-size:12px}.question{margin:17px 0 10px;font-weight:900}.equations{display:grid;gap:10px;margin:12px 0 18px}.equation{display:flex;justify-content:center;align-items:center;gap:9px;min-height:58px;padding:9px 12px;border:2px solid #e5c578;border-radius:16px;background:#fff7cf;font-size:26px;font-weight:900;letter-spacing:2px}.equation .equals{font-size:20px;color:#936d1d}.ask{text-align:center;font-size:18px;font-weight:900}.ask span{display:inline-grid;place-items:center;width:42px;height:42px;border-radius:12px;background:#fff;border:2px solid var(--ink);font-size:26px;vertical-align:middle}.answers{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;margin-top:15px}.answers button{padding:12px 6px;border:2px solid var(--ink);border-radius:13px;background:#fff;color:var(--ink);font-size:20px;font-weight:900;cursor:pointer;box-shadow:0 3px 0 var(--ink)}.answers button:disabled{cursor:default;opacity:.65}.answers button.correct{background:#bdf2d8}.answers button.wrong{background:#ffc7c7}.feedback{min-height:26px;margin-top:14px;text-align:center;font-weight:900}.feedback.good{color:#158254}.feedback.bad{color:#c04b4b}.result{text-align:center}.result-emoji{font-size:66px}.result h2{margin-bottom:8px}.result p{color:var(--muted)}.result-stats{display:flex;justify-content:center;gap:14px;margin:22px 0}.result-stats div{min-width:95px;padding:12px 8px;border-radius:16px;background:#f1efff}.result-stats strong,.result-stats span{display:block}.result-stats strong{font-size:27px;color:var(--purple)}.result-stats span{font-size:12px;color:var(--muted);margin-top:3px}.tip{text-align:center;color:#66768b;font-size:13px}@media(max-width:620px){.app{padding-top:21px}.hero{align-items:flex-start}.mascot{width:60px;height:60px;font-size:33px;border-radius:22px}.levels{grid-template-columns:1fr}.level{display:grid;grid-template-columns:auto 1fr;column-gap:10px}.level span{grid-row:span 2}.level small{grid-column:2}.panel{padding:18px}.equation{font-size:22px}.answers{grid-template-columns:repeat(2,1fr)}}