:root{--ink:#242553;--muted:#686a8f;--primary:#5b5ce2;--surface:#fff;--bg:#f1f4ff;--good:#157a55;--line:#d9ddfb;--shadow:0 10px 30px rgba(53,56,135,.12)}
*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.55 system-ui,-apple-system,"PingFang SC","Microsoft YaHei",sans-serif}.shell{max-width:760px;min-height:100dvh;margin:auto;padding:20px 16px 36px}.brand{display:flex;gap:10px;align-items:center;margin:4px 0 20px}.brand-mark{width:42px;height:42px;border-radius:14px;background:var(--primary);color:#fff;display:grid;place-items:center;font-weight:800}.card{background:var(--surface);border:1px solid var(--line);border-radius:20px;padding:20px;box-shadow:var(--shadow);margin:12px 0}.title{font-size:24px;line-height:1.25;margin:0 0 6px}.muted{color:var(--muted)}button{font:inherit;font-weight:700;border:0;border-radius:14px;min-height:48px;padding:11px 16px;cursor:pointer;touch-action:manipulation}button:focus-visible,input:focus-visible{outline:3px solid #ffb44c;outline-offset:2px}.primary{background:var(--primary);color:#fff}.secondary{background:#e9ebff;color:#37388c}.danger{background:#fee8e8;color:#9d2727}.stack{display:grid;gap:12px}.assignment{width:100%;text-align:left;background:#fff;border:1px solid var(--line);box-shadow:none}.assignment:hover{border-color:var(--primary)}.pill{display:inline-block;padding:2px 9px;background:#eceeff;color:#4647a7;border-radius:999px;font-size:13px;font-weight:700}.progress{height:9px;background:#e7e9f8;border-radius:99px;overflow:hidden;margin:12px 0}.progress>i{display:block;height:100%;background:linear-gradient(90deg,#5b5ce2,#8c64e8);border-radius:99px}.choice{display:grid;gap:10px;margin-top:18px}.choice button{background:#f7f7ff;color:var(--ink);border:2px solid #e1e3f8;text-align:left}.choice button.selected{border-color:var(--primary);background:#eceeff}.field{width:100%;min-height:50px;border:2px solid #dfe2f5;border-radius:14px;padding:10px;font:inherit}.nav{display:flex;justify-content:space-between;gap:10px;margin-top:20px}.question-label{font-weight:700;color:var(--primary)}.pair{display:grid;grid-template-columns:1fr 1fr;gap:10px;align-items:center}.pair select{min-height:46px;border:2px solid #dfe2f5;border-radius:12px;padding:6px;background:#fff;font:inherit}.order{display:grid;gap:8px}.order-item{display:flex;align-items:center;gap:8px;background:#f7f7ff;border:1px solid #e1e3f8;padding:10px;border-radius:12px}.order-item button{min-height:36px;padding:4px 10px}.result{font-size:20px;font-weight:800}.loading,.error{max-width:520px;margin:20vh auto;text-align:center;padding:24px}.notice{padding:12px;border-radius:12px;background:#fff8e9;color:#825b00}.review-answer{padding:12px;border-radius:12px;background:#f7f7ff;margin-top:10px}@media (prefers-reduced-motion:no-preference){.card{animation:in .18s ease-out}@keyframes in{from{opacity:.35;transform:translateY(6px)}to{opacity:1;transform:none}}}@media (max-width:420px){.shell{padding:14px 12px}.card{padding:16px}.title{font-size:22px}}