* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        
        body {
            font-family: 'SimSun', '宋体', serif;
            background: linear-gradient(135deg, #C4CAD8 0%, #22680C 100%);
            min-height: 100vh;
            display: flex;
            flex-direction: column;
            align-items: center;
            padding: 20px;
        }
        
        .container {
            max-width: 1400px;
            width: 100%;
            text-align: center;
        }
        
        h1 {
            color: #E9F3FF;
            font-size: 32px;
            font-weight: bold;
            margin-bottom: 30px;
            text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
        }
        
        .theorem-selector {
            background: rgba(255,255,255,0.15);
            backdrop-filter: blur(10px);
            border: 2px solid rgba(255,255,255,0.2);
            border-radius: 15px;
            padding: 25px;
            margin-bottom: 30px;
            box-shadow: 0 8px 32px rgba(0,0,0,0.1);
        }
        
        .theorem-title {
            color: #E9F3FF;
            font-size: 22px;
            font-weight: bold;
            margin-bottom: 20px;
        }
        
        .theorem-buttons {
            display: flex;
            gap: 15px;
            justify-content: center;
            flex-wrap: wrap;
        }
        
        .theorem-btn {
            background: linear-gradient(145deg, #2D73CC, #1a5aa0);
            color: white;
            border: none;
            padding: 12px 24px;
            border-radius: 8px;
            font-size: 18px;
            font-weight: bold;
            cursor: pointer;
            transition: all 0.3s ease;
            box-shadow: 0 4px 15px rgba(45,115,204,0.3);
        }
        
        .theorem-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(45,115,204,0.4);
        }
        
        .theorem-btn.active {
            background: linear-gradient(145deg, #38899B, #2a6b7a);
            box-shadow: 0 6px 20px rgba(56,137,155,0.5);
        }
        
        .control-panel {
            background: rgba(255,255,255,0.15);
            backdrop-filter: blur(10px);
            border: 2px solid rgba(255,255,255,0.2);
            border-radius: 15px;
            padding: 25px;
            margin-bottom: 30px;
            box-shadow: 0 8px 32px rgba(0,0,0,0.1);
        }
        
        .control-title {
            color: #E9F3FF;
            font-size: 20px;
            font-weight: bold;
            margin-bottom: 20px;
        }
        
        .control-row {
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 30px;
            margin: 15px 0;
            flex-wrap: wrap;
        }
        
        .control-group {
            display: flex;
            align-items: center;
            gap: 15px;
        }
        
        .control-label {
            color: #D9EAFF;
            font-size: 16px;
            min-width: 100px;
            text-align: right;
        }
        
        .control-input {
            width: 80px;
            padding: 8px;
            border: 2px solid rgba(255,255,255,0.3);
            border-radius: 6px;
            background: rgba(255,255,255,0.2);
            color: #E9F3FF;
            font-size: 16px;
            text-align: center;
        }
        
        .control-input:focus {
            outline: none;
            border-color: #38899B;
            background: rgba(255,255,255,0.3);
        }
        
        .reset-btn {
            background: linear-gradient(145deg, #389B74, #2a7a5a);
            color: white;
            border: none;
            padding: 10px 20px;
            border-radius: 6px;
            font-size: 16px;
            cursor: pointer;
            transition: all 0.3s ease;
        }
        
        .reset-btn:hover {
            transform: translateY(-1px);
            box-shadow: 0 4px 15px rgba(56,155,116,0.4);
        }
        
        .canvas-container {
            background: rgba(255,255,255,0.95);
            border: 3px solid rgba(255,255,255,0.3);
            border-radius: 15px;
            padding: 30px;
            margin-bottom: 30px;
            box-shadow: 0 12px 40px rgba(0,0,0,0.15);
        }
        
        #geometryCanvas {
            border: 2px solid #2D73CC;
            border-radius: 10px;
            cursor: crosshair;
            background: white;
        }
        
        .status-panel {
            background: rgba(255,255,255,0.15);
            backdrop-filter: blur(10px);
            border: 2px solid rgba(255,255,255,0.2);
            border-radius: 15px;
            padding: 25px;
            box-shadow: 0 8px 32px rgba(0,0,0,0.1);
        }
        
        .status-title {
            color: #E9F3FF;
            font-size: 20px;
            font-weight: bold;
            margin-bottom: 15px;
        }
        
        .measurement-display {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 15px;
            margin-bottom: 20px;
        }
        
        .measurement-item {
            background: rgba(255,255,255,0.2);
            padding: 12px;
            border-radius: 8px;
            border: 1px solid rgba(255,255,255,0.3);
        }
        
        .measurement-label {
            color: #D9EAFF;
            font-size: 14px;
            margin-bottom: 5px;
        }
        
        .measurement-value {
            color: #E9F3FF;
            font-size: 18px;
            font-weight: bold;
        }
        
        .congruence-result {
            background: rgba(56,137,155,0.3);
            border: 2px solid #38899B;
            border-radius: 10px;
            padding: 20px;
            margin-top: 20px;
        }
        
        .result-text {
            color: #E9F3FF;
            font-size: 20px;
            font-weight: bold;
        }
        
        .success {
            background: rgba(56,155,116,0.3);
            border-color: #389B74;
        }
        
        .success .result-text {
            color: #E9F3FF;
        }

        .footer {
            background: linear-gradient(to right);
            color: #ecf0f1;
            text-align: center;
            padding: 10px;
            margin-top: 15px;
            border-radius: 0 0 10px 10px;
        }
        
        @media (max-width: 768px) {
            .theorem-buttons {
                flex-direction: column;
                align-items: center;
            }
            
            .control-row {
                flex-direction: column;
                gap: 15px;
            }
            
            .measurement-display {
                grid-template-columns: 1fr;
            }
            
            h1 {
                font-size: 26px;
            }
            
            #geometryCanvas {
                width: 100%;
                height: 400px;
            }
        }