* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            background: linear-gradient(135deg, #EF5350 0%, #F44336 100%);
            min-height: 100vh;
            color: #fff;
            overflow-x: hidden;
            user-select: none;
        }

        .game-container {
            max-width: 900px;
            margin: 0 auto;
            padding: 20px;
            min-height: 100vh;
            display: flex;
            flex-direction: column;
            gap: 20px;
        }

        .game-header {
            text-align: center;
            background: rgba(255, 255, 255, 0.1);
            backdrop-filter: blur(20px);
            border-radius: 20px;
            padding: 25px;
            border: 1px solid rgba(255, 255, 255, 0.2);
        }

        .game-header h1 {
            font-size: 2.5rem;
            font-weight: 300;
            margin-bottom: 10px;
            letter-spacing: 3px;
            text-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
        }

        .game-subtitle {
            font-size: 1rem;
            opacity: 0.8;
            letter-spacing: 1px;
        }

        .difficulty-selector {
            background: rgba(255, 255, 255, 0.1);
            backdrop-filter: blur(20px);
            border-radius: 20px;
            padding: 25px;
            border: 1px solid rgba(255, 255, 255, 0.2);
        }

        .difficulty-selector h3 {
            text-align: center;
            margin-bottom: 20px;
            font-weight: 300;
            font-size: 1.3rem;
        }

        .difficulty-buttons {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
            gap: 15px;
        }

        .difficulty-btn {
            padding: 20px;
            border: none;
            border-radius: 15px;
            background: rgba(255, 255, 255, 0.1);
            color: white;
            cursor: pointer;
            transition: all 0.3s ease;
            text-align: center;
            border: 2px solid transparent;
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: 8px;
        }

        .difficulty-btn span {
            font-size: 2rem;
        }

        .difficulty-btn div {
            font-weight: 600;
            font-size: 1rem;
        }

        .difficulty-btn small {
            opacity: 0.7;
            font-size: 0.8rem;
        }

        .difficulty-btn:hover {
            background: rgba(255, 255, 255, 0.2);
            transform: translateY(-2px);
        }

        .difficulty-btn.active {
            background: rgba(255, 255, 255, 0.25);
            border-color: rgba(255, 255, 255, 0.5);
        }

        .game-stats {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
            gap: 15px;
        }

        .stat-card {
            background: rgba(255, 255, 255, 0.1);
            backdrop-filter: blur(20px);
            border-radius: 15px;
            padding: 20px;
            text-align: center;
            border: 1px solid rgba(255, 255, 255, 0.2);
        }

        .stat-value {
            font-size: 2rem;
            font-weight: 600;
            margin-bottom: 5px;
            text-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
        }

        .stat-label {
            font-size: 0.9rem;
            opacity: 0.8;
            text-transform: uppercase;
            letter-spacing: 1px;
        }

        .game-canvas-container {
            background: rgba(255, 255, 255, 0.1);
            backdrop-filter: blur(20px);
            border-radius: 20px;
            padding: 20px;
            border: 1px solid rgba(255, 255, 255, 0.2);
            display: flex;
            justify-content: center;
            align-items: center;
        }

        #gameCanvas {
            background: linear-gradient(135deg, #1a1a1a 0%, #000 100%);
            border-radius: 15px;
            border: 2px solid rgba(255, 255, 255, 0.2);
            cursor: none;
        }

        .controls-hint {
            text-align: center;
            margin-top: 15px;
            opacity: 0.8;
            font-size: 0.9rem;
        }

        .game-controls {
            display: flex;
            gap: 15px;
            justify-content: center;
            flex-wrap: wrap;
        }

        .btn {
            padding: 12px 24px;
            border: none;
            border-radius: 25px;
            background: #D32F2F;
            color: white;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            font-size: 0.9rem;
            box-shadow: 0 4px 15px rgba(211, 47, 47, 0.3);
            min-width: 120px;
        }

        .btn:hover {
            background: #C62828;
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(211, 47, 47, 0.4);
        }

        .btn:disabled {
            opacity: 0.5;
            cursor: not-allowed;
            transform: none;
        }

        .btn.start-btn {
            background: #4CAF50;
            box-shadow: 0 4px 15px rgba(76, 175, 80, 0.3);
        }

        .btn.start-btn:hover {
            background: #43A047;
        }

        .btn.secondary {
            background: rgba(255, 255, 255, 0.2);
            box-shadow: 0 4px 15px rgba(255, 255, 255, 0.1);
        }

        .btn.secondary:hover {
            background: rgba(255, 255, 255, 0.3);
        }

        .power-ups {
            background: rgba(255, 255, 255, 0.1);
            backdrop-filter: blur(20px);
            border-radius: 20px;
            padding: 25px;
            border: 1px solid rgba(255, 255, 255, 0.2);
        }

        .power-ups h3 {
            text-align: center;
            margin-bottom: 20px;
            font-weight: 300;
            font-size: 1.2rem;
        }

        .power-up-list {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 15px;
        }

        .power-up-item {
            display: flex;
            align-items: center;
            gap: 15px;
            padding: 15px;
            background: rgba(255, 255, 255, 0.1);
            border-radius: 12px;
            transition: all 0.3s ease;
        }

        .power-up-item.active {
            background: rgba(76, 175, 80, 0.3);
            border: 1px solid rgba(76, 175, 80, 0.5);
            animation: power-up-glow 2s ease-in-out infinite alternate;
        }

        @keyframes power-up-glow {
            from {
                box-shadow: 0 0 5px rgba(76, 175, 80, 0.3);
            }
            to {
                box-shadow: 0 0 15px rgba(76, 175, 80, 0.6);
            }
        }

        .power-up-icon {
            font-size: 2rem;
            width: 50px;
            text-align: center;
        }

        .power-up-info {
            flex: 1;
        }

        .power-up-name {
            font-weight: 600;
            margin-bottom: 5px;
        }

        .power-up-desc {
            font-size: 0.8rem;
            opacity: 0.8;
        }

        /* 弹窗样式 */
        .popup {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: rgba(0, 0, 0, 0.8);
            backdrop-filter: blur(10px);
            display: none;
            align-items: center;
            justify-content: center;
            z-index: 1000;
        }

        .popup.show {
            display: flex;
        }

        .popup-content {
            background: linear-gradient(135deg, #EF5350 0%, #F44336 100%);
            border-radius: 25px;
            padding: 40px;
            text-align: center;
            max-width: 500px;
            width: 90%;
            box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
            border: 2px solid rgba(255, 255, 255, 0.2);
            max-height: 80vh;
            overflow-y: auto;
        }

        .popup-content h2 {
            font-size: 2rem;
            margin-bottom: 25px;
            font-weight: 300;
        }

        .final-stats {
            display: grid;
            gap: 15px;
            margin-bottom: 25px;
        }

        .stat-display {
            display: flex;
            align-items: center;
            gap: 15px;
            padding: 15px;
            background: rgba(255, 255, 255, 0.1);
            border-radius: 15px;
        }

        .stat-icon {
            font-size: 2rem;
            width: 50px;
            text-align: center;
        }

        .popup-actions {
            display: flex;
            gap: 15px;
            justify-content: center;
            flex-wrap: wrap;
        }

        /* 响应式设计 */
        @media (max-width: 768px) {
            .game-container {
                padding: 15px;
                gap: 15px;
            }
            
            .game-header h1 {
                font-size: 2rem;
            }
            
            .difficulty-buttons {
                grid-template-columns: repeat(2, 1fr);
            }
            
            #gameCanvas {
                width: 100% !important;
                height: 300px !important;
            }
            
            .game-controls {
                flex-direction: column;
                align-items: center;
            }
            
            .btn {
                min-width: 200px;
            }
        }

        @media (max-width: 480px) {
            .difficulty-buttons {
                grid-template-columns: 1fr;
            }
            
            .game-stats {
                grid-template-columns: repeat(2, 1fr);
            }
            
            .power-up-list {
                grid-template-columns: 1fr;
            }
        }