#menuBtn{
        position: fixed;
        top: 20px;
        left: 20px;
        z-index: 20;
        width: auto;
        padding: 12px 18px;
        border: none;
        border-radius: 14px;
        background: rgba(20,40,80,0.85);
        color: #d8ecff;
        font-size: 15px;
        cursor: pointer;
        backdrop-filter: blur(10px);
        border: 1px solid rgba(120,180,255,0.25);
        box-shadow:
            0 0 18px rgba(0,140,255,0.25);
        transition: 0.25s;
    }
    #menuBtn:hover{
        transform: translateY(-2px);
        background: rgba(40,80,140,0.95);
        box-shadow:
            0 0 24px rgba(80,180,255,0.45);
    }

        :root {
            --bg-color: #060913;
            --panel-bg: rgba(13, 20, 36, 0.75);
            --panel-border: rgba(0, 242, 254, 0.25);
            --accent-cyan: #00f2fe;
            --accent-blue: #4facfe;
            --text-main: #e2e8f0;
            --text-muted: #94a3b8;
            --danger-color: #ff4b5c;
            --warning-color: #ffb703;
        }

        * {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
            user-select: none;
        }

        body {
            background-color: var(--bg-color);
            color: var(--text-main);
            font-family: 'Roboto', sans-serif;
            min-height: 100vh;
            overflow-x: hidden;
            display: flex;
            flex-direction: column;
        }

        /* 布局设计 */
        .app-container {
            display: flex;
            flex-direction: row;
            width: 100vw;
            height: 100vh;
            padding: 16px;
            gap: 16px;
            box-sizing: border-box;
        }

        /* 左侧 3D 渲染视图 */
        .viewport-container {
            flex: 1;
            position: relative;
            background: #000;
            border-radius: 12px;
            border: 1px solid var(--panel-border);
            overflow: hidden;
            box-shadow: 0 0 30px rgba(0, 242, 254, 0.1);
            min-height: 400px;
        }

        #canvas3d {
            width: 100%;
            height: 100%;
            display: block;
        }

        /* 参考系 UI 指示器 */
        .ref-badge {
            position: absolute;
            bottom: 16px;
            right: 16px;
            padding: 8px 16px;
            background: rgba(6, 9, 19, 0.85);
            border: 1px solid var(--accent-cyan);
            border-radius: 20px;
            font-family: 'Orbitron', sans-serif;
            font-size: 0.85rem;
            color: var(--accent-cyan);
            box-shadow: 0 0 10px rgba(0, 242, 254, 0.2);
            pointer-events: none;
            backdrop-filter: blur(6px);
            z-index: 10;
        }

        /* 触摸屏友好：视角切换控制按钮组 */
        .camera-controls {
            position: absolute;
            top: 16px;
            right: 16px;
            display: flex;
            gap: 8px;
            z-index: 10;
            background: rgba(6, 9, 19, 0.7);
            padding: 6px;
            border-radius: 10px;
            border: 1px solid rgba(0, 242, 254, 0.2);
            backdrop-filter: blur(6px);
        }

        .cam-btn {
            background: rgba(0, 242, 254, 0.1);
            border: 1px solid var(--accent-cyan);
            color: var(--accent-cyan);
            padding: 6px 12px;
            border-radius: 6px;
            font-family: 'Orbitron', sans-serif;
            font-size: 0.75rem;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.2s ease;
        }

        .cam-btn:hover, .cam-btn:active {
            background: var(--accent-cyan);
            color: #000;
            box-shadow: 0 0 12px rgba(0, 242, 254, 0.5);
        }

        /* 右侧 控制面板 */
        .sidebar {
            width: 380px;
            background: var(--panel-bg);
            border: 1px solid var(--panel-border);
            border-radius: 12px;
            padding: 24px;
            display: flex;
            flex-direction: column;
            gap: 20px;
            backdrop-filter: blur(12px);
            overflow-y: auto;
            box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
        }

        /* 自定义面板滚动条 */
        .sidebar::-webkit-scrollbar {
            width: 6px;
        }
        .sidebar::-webkit-scrollbar-track {
            background: rgba(0, 0, 0, 0.2);
            border-radius: 3px;
        }
        .sidebar::-webkit-scrollbar-thumb {
            background: var(--accent-cyan);
            border-radius: 3px;
        }

        /* 标题样式 */
        .header h1 {
            font-family: 'Orbitron', sans-serif;
            font-size: 1.35rem;
            font-weight: 800;
            letter-spacing: 1.5px;
            background: linear-gradient(135deg, var(--accent-cyan), var(--accent-blue));
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            margin-bottom: 6px;
        }

        .header p {
            font-size: 0.8rem;
            color: var(--text-muted);
            line-height: 1.4;
        }

        /* 控制组 */
        .control-group {
            display: flex;
            flex-direction: column;
            gap: 16px;
        }

        .section-title {
            font-family: 'Orbitron', sans-serif;
            font-size: 0.85rem;
            color: var(--accent-cyan);
            border-bottom: 1px solid rgba(0, 242, 254, 0.2);
            padding-bottom: 6px;
            letter-spacing: 1px;
            text-transform: uppercase;
        }

        .control-item {
            display: flex;
            flex-direction: column;
            gap: 6px;
        }

        .control-item label {
            font-size: 0.85rem;
            color: var(--text-main);
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .control-item label span.val {
            font-family: 'Orbitron', sans-serif;
            color: var(--accent-cyan);
            font-size: 0.9rem;
        }

        /* Slider 样式 */
        input[type=range] {
            -webkit-appearance: none;
            width: 100%;
            background: rgba(255, 255, 255, 0.08);
            height: 6px;
            border-radius: 3px;
            outline: none;
        }

        input[type=range]::-webkit-slider-thumb {
            -webkit-appearance: none;
            width: 16px;
            height: 16px;
            border-radius: 50%;
            background: var(--accent-cyan);
            cursor: pointer;
            box-shadow: 0 0 10px var(--accent-cyan);
            transition: transform 0.1s ease;
        }

        input[type=range]::-webkit-slider-thumb:hover {
            transform: scale(1.2);
        }

        /* Radio 控制 (参考系) */
        .radio-group {
            display: flex;
            gap: 12px;
            background: rgba(0, 0, 0, 0.2);
            padding: 4px;
            border-radius: 8px;
            border: 1px solid rgba(255, 255, 255, 0.05);
        }

        .radio-option {
            flex: 1;
            text-align: center;
        }

        .radio-option input[type="radio"] {
            display: none;
        }

        .radio-option label {
            display: block;
            padding: 8px;
            font-size: 0.85rem;
            cursor: pointer;
            border-radius: 6px;
            transition: all 0.3s ease;
            color: var(--text-muted);
        }

        .radio-option input[type="radio"]:checked + label {
            background: linear-gradient(135deg, rgba(0, 242, 254, 0.2), rgba(79, 172, 254, 0.2));
            color: var(--accent-cyan);
            border: 1px solid rgba(0, 242, 254, 0.4);
            font-weight: 500;
        }

        /* 按钮组 */
        .btn-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 12px;
        }

        .btn {
            background: rgba(0, 242, 254, 0.05);
            border: 1px solid var(--accent-cyan);
            color: var(--accent-cyan);
            padding: 12px;
            border-radius: 8px;
            font-family: 'Orbitron', sans-serif;
            font-size: 0.85rem;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 6px;
            box-shadow: 0 0 10px rgba(0, 242, 254, 0.05);
        }

        .btn:hover {
            background: var(--accent-cyan);
            color: #000;
            box-shadow: 0 0 20px rgba(0, 242, 254, 0.4);
        }

        .btn-explode {
            border-color: var(--warning-color);
            color: var(--warning-color);
        }

        .btn-explode:hover {
            background: var(--warning-color);
            color: #000;
            box-shadow: 0 0 20px rgba(255, 183, 3, 0.4);
        }

        .btn-reset {
            grid-column: span 2;
            border-color: rgba(255, 255, 255, 0.2);
            color: var(--text-muted);
        }

        .btn-reset:hover {
            background: rgba(255, 255, 255, 0.1);
            color: #fff;
            box-shadow: none;
        }

        .btn:disabled {
            opacity: 0.3;
            cursor: not-allowed;
            box-shadow: none;
            background: rgba(0, 0, 0, 0.1);
        }

        /* 响应式适配：页面变窄时转换为上下分行布局 */
        @media (max-width: 850px) {
            .app-container {
                flex-direction: column;
                height: auto;
                overflow-y: auto;
            }

            .viewport-container {
                height: 55vh;
                min-height: 350px;
                flex: none;
            }

            .sidebar {
                width: 100%;
                overflow-y: visible;
                flex: none;
            }
        }