.app{max-width:800px;margin:0 auto;padding:20px;font-family:Arial,sans-serif}.demo-section{margin:30px 0;padding:20px;border:1px solid #ddd;border-radius:8px;background:#f9f9f9}.demo-section h2{color:#333;border-bottom:2px solid #007bff;padding-bottom:10px;margin-top:0}.counter-demo,.form-demo,.api-demo,.local-storage-demo,.toggle-demo{padding:15px}.counter-group,.form-group,.toggle-group,.setting-group{margin:15px 0;padding:15px;border:1px solid #ccc;border-radius:5px;background:#fff}input,select,button{margin:5px;padding:8px 12px;border:1px solid #ddd;border-radius:4px}button{background:#007bff;color:#fff;border:none;cursor:pointer}button:hover{background:#0056b3}button.active{background:#28a745}.loading{color:#856404;background:#fff3cd;padding:10px;border-radius:4px}.error{color:#721c24;background:#f8d7da;padding:10px;border-radius:4px}.data-display{background:#f8f9fa;padding:10px;border-radius:4px;overflow-x:auto}.demo-note{font-style:italic;color:#6c757d;margin-top:15px;padding-top:10px;border-top:1px dashed #ccc}.dark-mode{background:#333;color:#fff}.dark-mode .toggle-group{background:#444;border-color:#555}