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

        body {
            font-family: 'Inter', sans-serif;
            background: #0a0f1c;
            color: #eef4ff;
            overflow-x: hidden;
        }

        /* Header */
        .main-header {
            background: rgba(10, 20, 30, 0.95);
            backdrop-filter: blur(8px);
            border-bottom: 1px solid rgba(72, 187, 255, 0.3);
            padding: 0.8rem 2rem;
            position: sticky;
            top: 0;
            z-index: 100;
        }
        .header-container {
            max-width: 1600px;
            margin: 0 auto;
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap;
            
        }
        .header-logo {
            font-size: 1.8rem;
            font-weight: 800;
            background: linear-gradient(135deg, #60efff, #00b4ff);
            -webkit-background-clip: text;
            background-clip: text;
            color: transparent;
        }
        .header-logo span { color: #f5b042; background: none; -webkit-background-clip: unset; background-clip: unset; }
        .nav-links a {
            color: #ccdeee;
            text-decoration: none;
            margin-left: 1.8rem;
            font-weight: 500;
            transition: 0.2s;
            
        }
        .nav-links a:hover { color: #60efff; }

        /* Main Layout */
        .sim-container {
            max-width: 1600px;
            margin: 1.5rem auto;
            padding: 0 1.5rem;
        }

        /* TABS (Top) - Categorized Tools */
        .tabs-container {
            background: rgba(20, 30, 45, 0.8);
            backdrop-filter: blur(12px);
            border-radius: 28px;
            padding: 0.5rem 1rem;
            margin-bottom: 1.5rem;
            border: 1px solid rgba(96, 239, 255, 0.2);
        }
        .tabs-header {
            display: flex;
            flex-wrap: wrap;
            gap: 0.5rem;
            border-bottom: 1px solid rgba(72, 187, 255, 0.3);
            padding-bottom: 0.5rem;
        }
        .tab-btn {
            background: transparent;
            border: none;
            padding: 10px 24px;
            font-size: 1rem;
            font-weight: 600;
            color: #b4cdff;
            cursor: pointer;
            border-radius: 40px;
            transition: 0.2s;
            display: flex;
            align-items: center;
            gap: 8px;
        }
        .tab-btn i { font-size: 1.1rem; }
        .tab-btn.active {
            background: #00b4ff22;
            color: #60efff;
            border-bottom: 2px solid #60efff;
            border-radius: 30px 30px 0 0;
        }
        .tab-btn:hover { background: #2c3e55; color: white; }
        .tab-content {
            padding: 1rem 0.5rem;
            display: none;
            animation: fade 0.25s ease;
        }
        .tab-content.active-tab { display: block; }
        .tools-grid {
            display: flex;
            flex-wrap: wrap;
            gap: 12px;
            margin-top: 8px;
        }
        .tool-card-3d {
            background: linear-gradient(145deg, #1e2a3a, #0f1722);
            border-radius: 20px;
            padding: 8px 18px;
            display: flex;
            align-items: center;
            gap: 10px;
            cursor: pointer;
            transition: all 0.2s cubic-bezier(0.2, 0.9, 0.4, 1.1);
            border: 1px solid #2d4a6e;
            box-shadow: 0 4px 10px rgba(0,0,0,0.2);
        }
        .tool-card-3d:hover {
            transform: translateY(-3px) scale(1.02);
            border-color: #60efff;
            box-shadow: 0 10px 20px rgba(0,180,255,0.2);
        }
        .tool-icon { font-size: 1.4rem; }
        .tool-info h4 { font-size: 0.9rem; font-weight: 700; }
        .tool-info p { font-size: 0.7rem; opacity: 0.7; }
        
        /* 3D Simulation Canvas + Log area */
        .simulation-workspace {
            display: flex;
            flex-direction: column;
            gap: 1rem;
        }
        .canvas-3d-area {
            background: #0a101c;
            border-radius: 32px;
            border: 1px solid #2d4f6e;
            overflow: hidden;
            box-shadow: 0 20px 35px rgba(0,0,0,0.5);
            position: relative;
        }
        #canvas3d {
            width: 100%;
            height: 500px;
            display: block;
            background: radial-gradient(circle at center, #111a28, #05080f);
        }
        .sim-controls {
            display: flex;
            justify-content: space-between;
            align-items: center;
            background: #0f1825cc;
            backdrop-filter: blur(8px);
            padding: 0.8rem 1.5rem;
            border-radius: 60px;
            margin-top: 10px;
            flex-wrap: wrap;
            gap: 12px;
        }
        .action-group button {
            background: #1e2f3e;
            border: none;
            padding: 8px 18px;
            border-radius: 40px;
            color: white;
            font-weight: 600;
            margin: 0 6px;
            cursor: pointer;
            transition: 0.2s;
        }
        .action-group button:hover { background: #2c5a6e; transform: scale(0.97); }
        .save-load-group button {
            background: #0f2c3a;
            border: 1px solid #60efff;
        }
        .log-panel {
            background: #07111eaa;
            border-radius: 24px;
            padding: 12px 20px;
            font-family: monospace;
            font-size: 0.85rem;
            border-left: 4px solid #60efff;
        }
        .gallery-section {
            margin-top: 2rem;
            background: #0f1825cc;
            border-radius: 32px;
            padding: 1.2rem;
        }
        .gallery-grid {
            display: flex;
            flex-wrap: wrap;
            gap: 16px;
            margin-top: 12px;
        }
        .gallery-item {
            background: #172433;
            border-radius: 20px;
            padding: 12px;
            width: 220px;
            cursor: pointer;
            transition: 0.2s;
            border: 1px solid #2f4b6e;
        }
        .gallery-item:hover { transform: translateY(-5px); border-color: #60efff; }
        footer {
            text-align: center;
            padding: 2rem;
            color: #7e95b0;
            margin-top: 3rem;
        }
        @keyframes fade { from { opacity: 0; } to { opacity: 1; } }
        @media (max-width: 900px) { .tabs-header { justify-content: center; } .tool-card-3d { padding: 4px 12px; } }