:root{--brand-primary: #2c3e50;--brand-secondary: #34495e;--brand-blue: #3498db;--brand-blue-dark: #2980b9;--brand-red: #e74c3c;--brand-red-dark: #c0392b;--brand-green: #2ecc71;--brand-orange: #e67e22;--brand-purple: #9b59b6;--brand-bg: linear-gradient(135deg, #f5f7fa 0%, #e4e7eb 100%)}*{box-sizing:border-box;margin:0;padding:0}body{font-family:Segoe UI,Tahoma,Geneva,Verdana,sans-serif;line-height:1.6;color:#333;background:var(--brand-bg);padding:54px 10px 10px;min-height:100vh}.brand-watermark{position:fixed;top:0;left:0;right:0;bottom:0;pointer-events:none;z-index:-1;background-image:url(/brand/%E6%B0%B4%E5%8D%B0%E9%BB%91.png);background-repeat:repeat;background-size:200px auto;background-position:center center;opacity:.035;mix-blend-mode:multiply}.header-bar{display:flex;flex-direction:column;position:fixed;top:0;left:0;right:0;background:linear-gradient(135deg,var(--brand-primary),var(--brand-secondary));color:#fff;z-index:1000;box-shadow:0 2px 8px 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12px;border-radius:20px;font-size:.9rem;font-weight:500;z-index:2;line-height:1.3}.topic-number{position:absolute;top:10px;left:10px;background:#e74c3ce6;color:#fff;padding:6px 12px;border-radius:20px;font-size:.9rem;font-weight:500;line-height:1.3;cursor:pointer;transition:transform .2s;z-index:10}.topic-number:hover{transform:scale(1.1)}.prompt-container{position:absolute;top:0;left:0;right:0;bottom:0;pointer-events:none;opacity:0;transition:opacity .3s;z-index:5}.prompt-container.visible{opacity:1}.prompt-item{position:absolute;font-size:1.3rem;color:#333;font-weight:600;background:#fffffff2;padding:10px 18px;border-radius:8px;box-shadow:0 2px 6px #00000026;pointer-events:auto;max-width:45%}.prompt-item.p1{top:18%;left:6%}.prompt-item.p2{top:18%;right:6%}.prompt-item.p3{bottom:18%;left:6%}.prompt-item.p4{bottom:18%;right:6%}.question-text{font-size:1.98rem;font-weight:600;color:var(--brand-primary);margin-bottom:15px;line-height:1.4;margin-top:40px}.card-hint{text-align:center;font-size:1.05rem;color:#7f8c8d;font-style:italic;margin-top:15px}.a2-back-content{display:flex;flex-direction:column;gap:15px;margin-top:40px;flex:1;padding:10px}.keywords-section,.connectors-section{background:#ffffff1a;border-radius:10px;padding:8px;flex:1;display:flex;flex-direction:row;align-items:stretch}.keywords-title,.connectors-title{font-size:.85rem;font-weight:600;writing-mode:vertical-rl;text-orientation:mixed;padding:8px 4px;border-radius:6px 0 0 6px;letter-spacing:2px;min-width:28px;display:flex;align-items:center;justify-content:center}.keywords-title{color:var(--brand-green);background:#2ecc7126}.connectors-title{color:var(--brand-red);background:#e74c3c26}.keywords-list,.connectors-list{display:grid;grid-template-columns:repeat(3,1fr);gap:6px;flex:1;align-content:center;padding:4px}.keyword{background:#3498dbcc;color:#fff;padding:8px 12px;border-radius:12px;font-size:.95rem;font-weight:500;text-align:center;display:flex;align-items:center;justify-content:center;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.connector{background:#e74c3ccc;color:#fff;padding:8px 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