:root{--primary-color: #4a90e2;--secondary-color: #f39c12;--background-color: #f4f7f9;--text-color: #333;--container-bg: #fff;--shadow-color: rgba(0, 0, 0, .1);--input-border-color: #ddd;--success-color: #27ae60;--error-color: #e74c3c;--transition-speed: .3s}[data-theme=dark]{--primary-color: #5ba3f5;--secondary-color: #f5b041;--background-color: #1a1a1a;--text-color: #e0e0e0;--container-bg: #2a2a2a;--shadow-color: rgba(0, 0, 0, .5);--input-border-color: #444;--success-color: #2ecc71;--error-color: #e67e73}*{box-sizing:border-box;margin:0;padding:0}body,html{height:100%;overflow:auto}body{font-family:Roboto,Arial,sans-serif;background-color:var(--background-color);color:var(--text-color);line-height:1.6}h1,h2,h3{color:var(--primary-color);margin-bottom:16px}h1{font-size:2em;text-align:center}h2{font-size:clamp(1rem,2vw,1.6em);border-bottom:2px solid var(--primary-color);padding-bottom:10px}.quiz-section 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