:root {
      --primary: #3498db;
      --secondary: #2c3e50;
      --accent: #e74c3c;
      --light: #ecf0f1;
      --dark: #34495e;
    }
    
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      font-family: 'Arial', sans-serif;
    }
    
    body {
      background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
      min-height: 100vh;
      padding: 20px;
    }
    
    header {
      display: flex;
      align-items: center;
      background: var(--secondary);
      color: white;
      padding: 15px 30px;
      border-radius: 10px;
      box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
      margin-bottom: 20px;
    }
    
    .logo {
      width: 60px;
      height: 60px;
      background: var(--primary);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-right: 15px;
      font-size: 24px;
      font-weight: bold;
    }
    
    .header-text {
      flex-grow: 1;
    }
    
    .header-text h1 {
      font-size: 1.8rem;
      margin-bottom: 5px;
    }
    
    .header-text p {
      font-size: 0.9rem;
      opacity: 0.8;
    }
    
    .container {
      display: flex;
      gap: 20px;
      margin-bottom: 20px;
    }
    
    .control-panel {
      flex: 1;
      background: white;
      padding: 20px;
      border-radius: 10px;
      box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    }
    
    .demo-area {
      flex: 2;
      background: white;
      border-radius: 10px;
      box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
      position: relative;
      overflow: hidden;
    }
    
    .demo-canvas {
      width: 100%;
      height: 100%;
      background: #f8f9fa;
    }
    
    .knowledge-section {
      background: white;
      padding: 20px;
      border-radius: 10px;
      box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
      margin-bottom: 20px;
    }
    
    footer {
      text-align: center;
      padding: 15px;
      background: var(--secondary);
      color: white;
      border-radius: 10px;
      font-size: 0.9rem;
    }
    
    h2 {
      color: var(--secondary);
      margin-bottom: 15px;
      padding-bottom: 10px;
      border-bottom: 2px solid var(--primary);
    }
    
    .control-group {
      margin-bottom: 15px;
    }
    
    label {
      display: block;
      margin-bottom: 5px;
      color: var(--dark);
      font-weight: bold;
    }
    
    input[type="range"] {
      width: 100%;
      margin-bottom: 5px;
    }
    
    .value-display {
      text-align: center;
      font-size: 1.1rem;
      color: var(--accent);
      font-weight: bold;
    }
    
    .btn-group {
      display: flex;
      gap: 10px;
      margin-top: 20px;
    }
    
    button {
      flex: 1;
      padding: 10px;
      border: none;
      border-radius: 5px;
      background: var(--primary);
      color: white;
      font-weight: bold;
      cursor: pointer;
      transition: all 0.3s;
    }
    
    button:hover {
      background: #2980b9;
      transform: translateY(-2px);
    }
    
    button.reset {
      background: var(--accent);
    }
    
    button.reset:hover {
      background: #c0392b;
    }
    
    .knowledge-points {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
      gap: 20px;
      margin-top: 15px;
    }
    
    .point-card {
      background: #f8f9fa;
      padding: 15px;
      border-radius: 8px;
      border-left: 4px solid var(--primary);
    }
    
    .point-card h3 {
      color: var(--primary);
      margin-bottom: 10px;
    }
    
    .point-card p {
      line-height: 1.6;
    }
    
    @media (max-width: 768px) {
      .container {
        flex-direction: column;
      }
    }