:root {
    --primary-color: #FF6B6B;
    --secondary-color: #4ECDC4;
    --accent-color: #FFE66D;
    --dark-color: #292F36;
    --light-color: #F7FFF7;
    --gradient-primary: linear-gradient(135deg, #FF6B6B 0%, #FF8E53 100%);
    --gradient-secondary: linear-gradient(135deg, #4ECDC4 0%, #45B7D1 100%);
    --shadow-sm: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 10px 20px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 20px 40px rgba(0, 0, 0, 0.2);
    --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
  }

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

  body {
    font-family: 'Roboto', sans-serif;
    line-height: 1.6;
    color: var(--dark-color);
    background-color: var(--light-color);
    padding: 0;
    margin: 0;
    overflow-x: hidden;
  }

  .container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
  }

  header {
    background: var(--gradient-primary);
    color: white;
    padding: 2rem 0;
    text-align: center;
    position: relative;
    overflow: hidden;
    margin-bottom: 3rem;
    box-shadow: var(--shadow-md);
  }

  header::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--accent-color);
  }

  header h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.2);
  }

  .header-subtitle {
    font-size: 1.2rem;
    opacity: 0.9;
    max-width: 800px;
    margin: 0 auto;
  }

  .notice {
    background: var(--accent-color);
    color: var(--dark-color);
    padding: 1rem;
    text-align: center;
    font-weight: bold;
    margin-bottom: 2rem;
    border-radius: 4px;
    box-shadow: var(--shadow-sm);
  }

  .nav-tabs {
    display: flex;
    justify-content: center;
    margin-bottom: 2rem;
    flex-wrap: wrap;
    gap: 1rem;
  }

  .nav-tab {
    padding: 0.8rem 1.5rem;
    background: white;
    border-radius: 50px;
    cursor: pointer;
    font-weight: bold;
    transition: var(--transition);
    box-shadow: var(--shadow-sm);
    color: var(--dark-color);
    border: none;
  }

  .nav-tab:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
    color: var(--primary-color);
  }

  .nav-tab.active {
    background: var(--gradient-primary);
    color: white;
  }

  .content-section {
    background: white;
    border-radius: 8px;
    padding: 2rem;
    margin-bottom: 3rem;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
  }

  .content-section:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-5px);
  }

  .content-section h2 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    font-size: 1.8rem;
    position: relative;
    padding-bottom: 0.5rem;
  }

  .content-section h2::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 0;
    width: 50px;
    height: 3px;
    background: var(--gradient-primary);
    border-radius: 3px;
  }

  .content-section p {
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
    line-height: 1.7;
  }

  pre {
    background: #292D3E;
    color: #A6ACCD;
    padding: 1.5rem;
    border-radius: 8px;
    overflow-x: auto;
    margin: 2rem 0;
    box-shadow: var(--shadow-md);
    font-family: 'Fira Code', monospace;
    font-size: 0.95rem;
    line-height: 1.5;
  }

  code {
    font-family: 'Fira Code', monospace;
    background: rgba(255, 107, 107, 0.1);
    color: var(--primary-color);
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    font-size: 0.9rem;
  }

  .image-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
    margin: 2rem 0;
  }

  .image-card {
    border-radius: 8px;
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
    position: relative;
  }

  .image-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
  }

  .image-card img {
    width: 100%;
    height: auto;
    display: block;
    transition: var(--transition);
  }

  .image-card:hover img {
    transform: scale(1.05);
  }

  .image-card::after {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(to top, rgba(0,0,0,0.5), transparent);
    opacity: 0;
    transition: var(--transition);
  }

  .image-card:hover::after {
    opacity: 1;
  }

  .summary-box {
    background: var(--gradient-secondary);
    color: white;
    padding: 2rem;
    border-radius: 8px;
    margin: 3rem 0;
    box-shadow: var(--shadow-md);
    position: relative;
    overflow: hidden;
  }

  .summary-box::before {
    content: "";
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255,255,255,0.1) 0%, transparent 70%);
    transform: rotate(30deg);
    animation: shine 6s infinite linear;
  }

  @keyframes shine {
    0% { transform: rotate(30deg) translate(-30%, -30%); }
    100% { transform: rotate(30deg) translate(30%, 30%); }
  }

  .summary-box h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    position: relative;
    z-index: 1;
  }

  .summary-box p {
    position: relative;
    z-index: 1;
  }

  footer {
    text-align: center;
    padding: 2rem 0;
    background: var(--dark-color);
    color: white;
    margin-top: 3rem;
  }

  @media (max-width: 768px) {
    header h1 {
      font-size: 2rem;
    }
    
    .header-subtitle {
      font-size: 1rem;
    }
    
    .content-section {
      padding: 1.5rem;
    }
    
    .image-grid {
      grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    }
  }

  @media (max-width: 480px) {
    header h1 {
      font-size: 1.8rem;
    }
    
    .nav-tabs {
      flex-direction: column;
      align-items: center;
    }
    
    .nav-tab {
      width: 100%;
      max-width: 300px;
    }
    
    .content-section h2 {
      font-size: 1.5rem;
    }
    
    pre {
      padding: 1rem;
      font-size: 0.85rem;
    }
  }