* {margin:0; padding:0; box-sizing:border-box;}
    body {
      font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
      line-height: 1.6;
      color: #302f2f;
      background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
      min-height: 100vh;
      padding: 20px;  
    }
    .container {
      max-width: 900px;
      margin: 0 auto;
      background: rgba(255, 255, 255, 0.95);
      border-radius: 20px;
      box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
      backdrop-filter: blur(10px);
      overflow: hidden;
      padding: 20px;
    }
    .back-button {
      background: linear-gradient(45deg, #3498db, #2980b9);
      color:white; padding:12px 25px; border-radius:25px;
      text-decoration:none; margin-bottom:30px; display:inline-block;
    }
    .header {text-align:center; color: rgb(67, 64, 64);}
    .header h1 {font-size:3em; margin-bottom:10px; text-shadow:2px 2px 4px rgba(29,16,44,0.3);}
    .header p {font-size:1.2em; opacity:0.9;}
    .content {padding:40px;}
    .section {
      margin-bottom:40px;
      padding:30px;
      background: rgba(251,251,251,0.972);
      border-radius:15px;
      border-left: 5px solid #2980b9;
      transition: transform 0.3s ease;
    }
    .section:hover {transform: translateY(-5px); box-shadow:0 10px 20px rgba(0,0,0,0.1);}
    .section h2 {color:#2c3e50; margin-bottom:20px; font-size:2em; display:flex; align-items:center; gap:10px;}
    .icon {font-size:1.2em;}
    .examples-grid {
      display:grid;
      grid-template-columns:repeat(auto-fit, minmax(250px,1fr));
      gap:20px;
      margin:20px 0;
    }
    .example-card {
      background: linear-gradient(135deg, #f6f6f6 0%, #ffffff 100%);
      padding:20px;
      border-radius:10px;
      box-shadow:0 5px 15px rgba(0,0,0,0.1);
    }
    .example-card h4 {color:#2c3e50; margin-bottom:10px;}
    .example-card p {margin:5px 0; font-size:1.1em;}
    .key-points {
      background: linear-gradient(135deg, #ffecd2 0%, #fcb69f 100%);
      padding:30px;
      border-radius:15px;
      margin:20px 0;
    }
    .key-points li {
      margin:10px 0;
      padding:10px;
      background: rgba(255,255,255,0.7);
      border-radius:8px;
      border-left:4px solid #ff6b6b;
      font-weight:500;
    }
    .activity {
      background: linear-gradient(135deg, #d299c2 0%, #fef9d7 100%);
      padding:30px;
      border-radius:15px;
      margin:20px 0;
    }
    .question {
      background: rgba(255,255,255,0.7);
      padding:15px;
      margin:15px 0;
      border-radius:8px;
      border-left:4px solid #9b59b6;
    }
    .input-field {
      width:100%;
      padding:10px;
      margin:10px 0;
      border:2px solid #ddd;
      border-radius:5px;
      font-size:1em;
    }
    .check-btn {
      background: linear-gradient(135deg, #36d1dc 0%, #5b86e5 100%);
      color:white;
      border:none;
      padding:12px 25px;
      border-radius:25px;
      cursor:pointer;
      font-size:1em;
      transition: transform 0.2s ease;
    }
    .check-btn:hover {transform:scale(1.05);}
    .result {
      margin:10px 0;
      padding:10px;
      border-radius:5px;
      font-weight:bold;
    }
    .correct {background:#d4edda; color:#155724; border:1px solid #c3e6cb;}
    .incorrect {background:#f8d7da; color:#721c24; border:1px solid #f5c6cb;}
    .choice-btn {
      background: linear-gradient(135deg, #36d1dc 0%, #5b86e5 100%);
      color: white;
      border: none;
      padding: 12px 25px;
      border-radius: 25px;
      cursor: pointer;
      font-size: 1em;
      margin-right: 10px;
      margin-top: 10px;
      transition: transform 0.2s ease;
    }
    .choice-btn:hover { transform: scale(1.05); }