*{box-sizing:border-box;margin:0;padding:0}
  :root{--bg:#f4f6f9;--card:#fff;--primary:#4a90e2;--primary-soft:#e8f1fc;--text:#2c3e50;--text-sub:#7b8a99;--border:#eef1f5;--shadow:0 2px 12px rgba(0,0,0,.06);--radius:16px}
  body{font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",sans-serif;background:var(--bg);color:var(--text);min-height:100vh;padding:24px}
  .app{max-width:1440px;margin:0 auto}
  .card{background:var(--card);border-radius:var(--radius);box-shadow:var(--shadow);padding:26px}
  .header{display:flex;align-items:center;justify-content:space-between;margin-bottom:22px}
  .header h1{font-size:22px;font-weight:600}
  .back{font-size:13px;color:var(--text-sub);text-decoration:none;padding:6px 12px;background:var(--bg);border-radius:8px}
  .back:hover{background:var(--primary-soft);color:var(--primary)}
  .section{background:var(--bg);border-radius:12px;padding:16px;margin-bottom:14px}
  .section h3{font-size:15px;margin-bottom:12px;color:var(--text)}
  .row{display:flex;gap:8px;align-items:center;margin-bottom:10px;flex-wrap:wrap}
  .row input{flex:1;min-width:80px;padding:9px 10px;border:1px solid var(--border);border-radius:8px;font-size:14px}
  .row span{color:var(--text-sub);font-size:14px}
  input:focus{outline:none;border-color:var(--primary)}
  .answer{background:var(--primary-soft);color:var(--primary);padding:10px 12px;border-radius:8px;font-weight:600;font-size:15px;margin-top:8px}
  .toast{position:fixed;bottom:30px;left:50%;transform:translateX(-50%) translateY(20px);background:var(--text);color:#fff;padding:10px 20px;border-radius:10px;font-size:13px;opacity:0;transition:all .3s;pointer-events:none}
  .toast.show{opacity:1;transform:translateX(-50%) translateY(0)}