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

  body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    overflow: hidden;
  }

  .presentation {
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
  }

  .slide {
    display: none;
    width: 90%;
    max-width: 1000px;
    text-align: center;
    padding: 40px;
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    border: 1px solid rgba(255, 255, 255, 0.2);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
  }

  .slide.active {
    display: block;
    animation: slideIn 0.5s ease-out;
  }

  @keyframes slideIn {
    from {
      opacity: 0;
      transform: translateY(30px);
    }

    to {
      opacity: 1;
      transform: translateY(0);
    }
  }

  h1 {
    font-size: 3em;
    margin-bottom: 30px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
  }

  h2 {
    font-size: 2.5em;
    margin-bottom: 20px;
    color: #FFD700;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
  }

  h3 {
    font-size: 1.8em;
    margin-bottom: 15px;
    color: #87CEEB;
  }

  p {
    font-size: 1.4em;
    line-height: 1.6;
    margin-bottom: 20px;
  }

  ul {
    text-align: left;
    font-size: 1.3em;
    line-height: 1.8;
    margin: 20px 0;
    padding-left: 40px;
  }

  li {
    margin-bottom: 10px;
  }

  .code-demo {
    background: rgba(0, 0, 0, 0.4);
    padding: 20px;
    border-radius: 10px;
    margin: 20px 0;
    font-family: 'Courier New', monospace;
    text-align: left;
    border: 2px solid rgba(255, 255, 255, 0.3);
  }

  .code-demo pre {
    color: #fff;
    font-size: 1.1em;
    line-height: 1.4;
  }

  .css-property {
    color: #ff6b6b;
  }

  .css-value {
    color: #4ecdc4;
  }

  .css-selector {
    color: #FFD700;
  }

  .html-tag {
    color: #ff6b6b;
  }

  .html-content {
    color: #4ecdc4;
  }

  .js-keyword {
    color: #ff6b6b;
  }

  .js-string {
    color: #4ecdc4;
  }

  .js-number {
    color: #FFD700;
  }

  .js-variable {
    color: #87CEEB;
  }

  .js-comment {
    color: #95a5a6;
    font-style: italic;
  }

  .navigation {
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    gap: 20px;
  }

  button {
    padding: 12px 24px;
    font-size: 1.1em;
    background: rgba(255, 255, 255, 0.2);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: 25px;
    cursor: pointer;
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
  }

  button:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
  }

  button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
  }

  .slide-number {
    position: fixed;
    top: 20px;
    right: 20px;
    font-size: 1.2em;
    background: rgba(0, 0, 0, 0.3);
    padding: 10px 15px;
    border-radius: 20px;
  }

  .activity-box {
    background: rgba(255, 215, 0, 0.2);
    border: 2px solid #FFD700;
    border-radius: 15px;
    padding: 25px;
    margin: 20px 0;
  }

  .activity-box h3 {
    color: #FFD700;
    margin-bottom: 15px;
  }

  .comparison {
    display: flex;
    justify-content: space-around;
    margin: 30px 0;
    flex-wrap: wrap;
  }

  .comparison-item {
    background: rgba(255, 255, 255, 0.2);
    padding: 20px;
    border-radius: 15px;
    margin: 10px;
    min-width: 200px;
    flex: 1;
  }

  .console-demo {
    background: #1e1e1e;
    color: #fff;
    padding: 15px;
    border-radius: 8px;
    margin: 15px 0;
    font-family: 'Courier New', monospace;
    border: 2px solid #333;
  }

  .console-input {
    color: #4fc3f7;
  }

  .console-output {
    color: #81c784;
  }

  .data-type-box {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
    margin: 20px 0;
  }

  .type-card {
    background: rgba(255, 255, 255, 0.15);
    padding: 15px;
    border-radius: 10px;
    border: 2px solid rgba(255, 255, 255, 0.2);
  }

  .homework-box {
    background: rgba(255, 107, 107, 0.17);
    border: 2px solid #ff6b6b;
    border-radius: 15px;
    padding: 25px;
    margin: 20px 0;
    text-align: left;
  }

  .homework-box h3 {
    color: #ff6b6b;
    margin-bottom: 15px;
    text-align: center;
  }

  .homework-requirements {
    background: rgba(0, 0, 0, 0.2);
    padding: 15px;
    border-radius: 8px;
    margin: 15px 0;
  }

  .before-after {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin: 20px 0;
  }

  .before,
  .after {
    padding: 20px;
    border-radius: 10px;
    border: 2px solid rgba(255, 255, 255, 0.3);
  }

  .before {
    background: rgba(255, 0, 0, 0.1);
  }

  .after {
    background: rgba(0, 255, 0, 0.1);
  }

  .browser-window {
    background: #f0f0f0;
    border-radius: 10px;
    padding: 20px;
    color: #333;
    border: 3px solid #ccc;
    margin: 20px 0;
    text-align: left;
  }

  .browser-bar {
    background: #ddd;
    padding: 10px;
    border-radius: 5px 5px 0 0;
    margin: -20px -20px 15px -20px;
    color: #666;
    font-size: 0.9em;
    text-align: left;
  }

  .demo-box {
    border: 2px solid #333;
    padding: 15px;
    margin: 10px 0;
    background: white;
    color: #333;
    border-radius: 5px;
  }

  .demo-box.styled {
    background: linear-gradient(45deg, #ff6b6b, #4ecdc4);
    color: white;
    font-family: Arial, sans-serif;
    font-size: 18px;
    text-align: center;
    border-radius: 15px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.3);
  }

  @media (max-width: 768px) {
    h1 {
      font-size: 2em;
    }

    h2 {
      font-size: 1.8em;
    }

    p,
    ul {
      font-size: 1.1em;
    }

    .slide {
      padding: 20px;
    }

    .before-after {
      grid-template-columns: 1fr;
    }

    .comparison {
      flex-direction: column;
    }

    .data-type-box {
      grid-template-columns: 1fr;
    }
  }