:root{--primary-color: #2c3e50;--secondary-color: #3498db;--success-color: #2ecc71;--danger-color: #e74c3c;--bg-color: #f0f2f5;--widget-bg-color: #ffffff;--text-color: #333}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica,Arial,sans-serif;background-color:var(--bg-color);color:var(--text-color);margin:0}.container{max-width:1000px;margin:2rem auto;padding:2rem;background-color:var(--widget-bg-color);border-radius:8px;box-shadow:0 4px 6px #0000001a}.text-center{text-align:center}h1{color:var(--primary-color);margin-bottom:1rem}h2{text-align:center;margin-bottom:.5rem}.instructions{text-align:center;font-size:1.2rem;margin-top:0}.final-score{font-size:1.5rem;margin:2rem 0}.share-text-display{background-color:#f8f8f8;border:1px solid #eee;padding:1rem;margin:1rem auto;white-space:pre-wrap;word-break:break-all;font-family:monospace;text-align:left;max-width:500px}.btn{padding:.8rem 1.5rem;border:none;border-radius:4px;cursor:pointer;font-size:1rem;font-weight:500;transition:background-color .2s,transform .2s}.btn:hover{transform:translateY(-2px)}.btn-primary{background-color:var(--secondary-color);color:#fff}.btn-secondary{background-color:#95a5a6;color:#fff}.button-group{display:flex;flex-direction:column;align-items:center;gap:1rem;margin-top:1rem}.visualizer-area{margin:2rem 0;padding:1rem;background-color:#f8f9fa;border-radius:8px}.year-control{display:flex;flex-direction:column;align-items:center;margin:0 auto 1rem;max-width:500px}.year-control label{margin-bottom:.5rem;font-weight:500}.slider-container{display:flex;align-items:center;width:100%}.slider-container button{margin:0 .5rem;padding:.3rem .6rem;border:none;border-radius:4px;background-color:var(--secondary-color);color:#fff;cursor:pointer;font-size:1rem}.slider-container button:disabled{background-color:#ccc;cursor:not-allowed}.slider{-webkit-appearance:none;flex-grow:1;padding:0;height:10px;background:#ddd;outline:none;opacity:.7;transition:opacity .2s}.slider:hover{opacity:1}.slider::-webkit-slider-thumb{-webkit-appearance:none;-moz-appearance:none;appearance:none;width:20px;height:20px;background:var(--secondary-color);cursor:pointer;border-radius:50%}.chart-container{position:relative;height:60vh}.answer-area{margin-top:2rem}.options-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:1rem}.option-btn{width:100%;background-color:#ecf0f1;color:var(--primary-color)}.option-btn:disabled{transform:none}.option-btn.correct{background-color:var(--success-color);color:#fff}.option-btn.incorrect{background-color:var(--danger-color);color:#fff}.feedback-area{text-align:center;margin-top:1.5rem}.feedback-text{font-size:1.2rem;font-weight:500}.correct-text{color:var(--success-color)}.feedback-area button{margin-top:1rem}.share-feedback{margin-top:1rem;font-size:1rem;color:var(--secondary-color)}.difficulty-display{text-align:center;font-size:1.1rem;margin-bottom:1rem;color:#555}.loading,.error{text-align:center;padding:3rem;font-size:1.2rem;color:var(--danger-color)}.difficulty-selection{margin:1.5rem auto;padding:1rem;background-color:#f0f0f0;border-radius:8px;display:block;max-width:fit-content;text-align:left}.difficulty-selection label{font-weight:700;margin-right:1rem;display:block;margin-bottom:1rem}.seed-selection{margin:1.5rem auto;padding:1rem;background-color:#f0f0f0;border-radius:8px;display:block;max-width:fit-content}.seed-selection label{font-weight:700;margin-right:1rem}.seed-input-field{padding:.5rem;border:1px solid #ccc;border-radius:4px;font-size:1rem;width:200px}.radio-group{display:inline-block}.radio-group input[type=radio]{margin-right:.5rem}.radio-group label{margin-right:1rem;font-weight:400}