:root{--primary: #e8722a;--primary-dark: #d4611c;--bg: #f5f6f8;--text: #333;--text-light: #888}*{box-sizing:border-box}body{margin:0;font-family:PingFang SC,Microsoft YaHei,Helvetica Neue,Arial,sans-serif;background:var(--bg);color:var(--text)}a{color:inherit;text-decoration:none}.page{max-width:1200px;margin:0 auto;padding:20px 16px}.card{background:#fff;border-radius:8px;padding:20px}.rich-content p{margin:0 0 8px;line-height:1.8}.rich-content img{max-width:100%}.rich-content table{border-collapse:collapse;margin:8px 0}.rich-content td,.rich-content th{border:1px solid #ddd;padding:4px 10px}.option-item{display:flex;gap:12px;align-items:flex-start;padding:10px 14px;border-radius:8px;cursor:pointer;margin-bottom:8px;border:1px solid transparent;transition:background .15s}.option-item:hover{background:#faf6f1}.option-item.selected{background:#fdf1e7;border-color:var(--primary)}.option-item .option-label{flex:none;width:26px;height:26px;border-radius:50%;border:1px solid #bbb;display:flex;align-items:center;justify-content:center;font-size:13px;color:#666;margin-top:2px}.option-item.selected .option-label{background:var(--primary);border-color:var(--primary);color:#fff}.option-item.correct{background:#f0faf4;border-color:#52c41a}.option-item.correct .option-label{background:#52c41a;border-color:#52c41a;color:#fff}.option-item.wrong{background:#fff1f0;border-color:#ff4d4f}.option-item.wrong .option-label{background:#ff4d4f;border-color:#ff4d4f;color:#fff}.option-item.disabled{cursor:default}.answer-card-num{display:inline-flex;align-items:center;justify-content:center;width:32px;height:32px;border:1px solid #ddd;border-radius:6px;margin:4px;cursor:pointer;font-size:13px;background:#fff;-webkit-user-select:none;user-select:none}.answer-card-num.active{border-color:var(--primary);color:var(--primary);font-weight:600}.answer-card-num.right{background:#52c41a;border-color:#52c41a;color:#fff}.answer-card-num.wrong{background:#ff4d4f;border-color:#ff4d4f;color:#fff}.practice-layout{display:flex;gap:16px;align-items:flex-start}.practice-main{flex:1;min-width:0}.practice-side{width:300px;flex:none;position:sticky;top:16px}@media (max-width: 900px){.practice-layout{flex-direction:column}.practice-side{width:100%;position:static}}