:root {
    --primary: #1a73e8;
    --primary-dark: #0d47a1;
    --secondary: #f57c00;
    --light: #f5f5f5;
    --dark: #212121;
    --gray: #757575;
    --light-gray: #e0e0e0;
    --white: #ffffff;
    --success: #4caf50;
    --warning: #ff9800;
    --danger: #f44336;
    --border-radius: 8px;
    --shadow: 0 4px 6px rgba(0,0,0,0.1);
    --transition: all 0.3s ease;
  }

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

  body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #f5f7fa 0%, #e4edf5 100%);
    color: var(--dark);
    line-height: 1.6;
    padding: 0;
    margin: 0;
    min-height: 100vh;
    position: relative;
    padding-bottom: 60px;
  }

  .container {
    display: flex;
    max-width: 1400px;
    margin: 0 auto;
    padding: 20px;
    gap: 30px;
  }

  header {
    background: linear-gradient(to right, var(--primary), var(--primary-dark));
    color: white;
    padding: 1.5rem 2rem;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
  }

  .header-content {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
  }

  h1 {
    font-size: 1.8rem;
    font-weight: 700;
    margin: 0;
  }

  .header-controls {
    display: flex;
    gap: 15px;
  }

  .btn {
    background: rgba(255,255,255,0.2);
    border: none;
    color: white;
    padding: 8px 16px;
    border-radius: 4px;
    cursor: pointer;
    font-weight: 500;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 5px;
  }

  .btn:hover {
    background: rgba(255,255,255,0.3);
  }

  .sidebar {
    flex: 0 0 300px;
    background: var(--white);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    padding: 20px;
    height: fit-content;
    position: sticky;
    top: 100px;
    max-height: 80vh;
    overflow-y: auto;
  }

  .sidebar-title {
    font-size: 1.4rem;
    font-weight: 600;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--primary);
    color: var(--primary-dark);
  }

  .spis-tresci {
    padding-right: 10px;
  }

  .spis-tresci ol {
    list-style-type: none;
    counter-reset: section;
    padding-left: 0;
  }

  .spis-tresci > ol > li {
    margin-bottom: 15px;
    position: relative;
  }

  .spis-tresci > ol > li > a {
    display: block;
    font-weight: 600;
    color: var(--primary-dark);
    padding: 8px 0;
    text-decoration: none;
    transition: var(--transition);
    border-bottom: 1px solid var(--light-gray);
  }

  .spis-tresci > ol > li > a:hover {
    color: var(--secondary);
  }

  .spis-tresci ol ol {
    padding-left: 20px;
    margin-top: 10px;
  }

  .spis-tresci ol ol li {
    position: relative;
    margin-bottom: 8px;
  }

  .spis-tresci ol ol li a {
    display: block;
    color: var(--dark);
    text-decoration: none;
    padding: 5px 0;
    transition: var(--transition);
    font-size: 0.95rem;
  }

  .spis-tresci ol ol li a:hover {
    color: var(--primary);
    padding-left: 5px;
  }

  .spis-tresci ol ol ol {
    padding-left: 20px;
  }

  .spis-tresci ol ol ol li a {
    font-size: 0.85rem;
    color: var(--gray);
  }

  .main-content {
    flex: 1;
  }

  .temat {
    background: var(--white);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    padding: 30px;
    margin-bottom: 25px;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    position: relative;
    overflow: hidden;
  }

  .temat:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 15px rgba(0,0,0,0.1);
  }

  .temat::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 5px;
    height: 100%;
    background: var(--primary);
  }

  .temat[data-temat]::after {
    content: attr(data-temat);
    display: block;
    font-size: 1.7rem;
    font-weight: 700;
    margin-bottom: 20px;
    color: var(--primary-dark);
    padding-bottom: 15px;
    border-bottom: 1px solid var(--light-gray);
  }

  .sekcja {
    margin-bottom: 25px;
    padding: 15px;
    border-radius: var(--border-radius);
    background: rgba(245, 245, 245, 0.5);
  }

  .sekcja-title {
    font-size: 1.3rem;
    font-weight: 600;
    margin-bottom: 15px;
    color: var(--primary-dark);
    display: flex;
    align-items: center;
  }

  .sekcja-title::before {
    content: '';
    display: inline-block;
    width: 8px;
    height: 8px;
    background: var(--secondary);
    border-radius: 50%;
    margin-right: 10px;
  }

  .sekcja > ul, .sekcja > ol {
    padding-left: 30px;
  }

  .sekcja li {
    margin-bottom: 10px;
    position: relative;
  }

  .wzor {
    background: #e8f0fe;
    border-left: 4px solid var(--primary);
    padding: 15px;
    padding-left: 30px;
    margin: 15px 0;
    border-radius: 4px;
    font-family: "Courier New", monospace;
    font-size: 1.1rem;
    position: relative;
    overflow-x: auto;
  }

  .wzor::before {
    content: 'Wzór:';
    position: absolute;
    top: 5px;
    right: 10px;
    font-size: 0.8rem;
    color: var(--gray);
    font-family: Arial, sans-serif;
  }

  .tip-box {
    background: #e3f2fd;
    border-left: 4px solid var(--primary);
    padding: 15px;
    margin: 15px 0;
    border-radius: 4px;
  }

  .tip-title {
    font-weight: 600;
    color: var(--primary-dark);
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    gap: 8px;
  }

  .tip-title::before {
    content: '💡';
  }

  .example-box {
    background: #f1f8e9;
    border-left: 4px solid var(--success);
    padding: 15px;
    margin: 15px 0;
    border-radius: 4px;
  }

  .example-title {
    font-weight: 600;
    color: #2e7d32;
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    gap: 8px;
  }

  .example-title::before {
    content: '📝';
  }

  .warning-box {
    background: #fff8e1;
    border-left: 4px solid var(--warning);
    padding: 15px;
    margin: 15px 0;
    border-radius: 4px;
  }

  .warning-title {
    font-weight: 600;
    color: var(--warning);
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    gap: 8px;
  }

  .warning-title::before {
    content: '⚠️';
  }

  #backToTop {
    position: fixed;
    bottom: 30px;
    right: 30px;
    display: none;
    padding: 12px 18px;
    font-size: 18px;
    border: none;
    border-radius: 50%;
    background: var(--primary);
    color: var(--white);
    cursor: pointer;
    box-shadow: var(--shadow);
    transition: var(--transition);
    z-index: 99;
  }

  #backToTop:hover {
    background: var(--primary-dark);
    transform: translateY(-3px);
  }

  footer {
    position: absolute;
    bottom: 0;
    width: 100%;
    background: var(--dark);
    color: var(--white);
    text-align: center;
    padding: 20px;
    font-size: 0.9rem;
  }

  .progress-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 5px;
    background: transparent;
    z-index: 1000;
  }

  .progress-bar {
    height: 5px;
    background: var(--secondary);
    width: 0%;
    transition: width 0.2s ease;
  }

  .section-nav {
    display: flex;
    justify-content: space-between;
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid var(--light-gray);
  }

  .nav-btn {
    padding: 10px 20px;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-weight: 500;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 8px;
  }

  .nav-btn:hover {
    background: var(--primary-dark);
  }

  .nav-btn.prev::before {
    content: '←';
  }

  .nav-btn.next::after {
    content: '→';
  }

  @media (max-width: 992px) {
    .container {
      flex-direction: column;
    }
    
    .sidebar {
      position: relative;
      top: 0;
      margin-bottom: 30px;
      max-height: 400px;
    }
  }

  @media (max-width: 768px) {
    .header-content {
      flex-direction: column;
      gap: 15px;
      text-align: center;
    }
    
    .temat {
      padding: 20px;
    }
    
    .temat[data-temat]::after {
      font-size: 1.5rem;
    }
    
    .spis-tresci ol ol {
      padding-left: 15px;
    }
  }

  @media (max-width: 480px) {
    .sekcja-title {
      font-size: 1.1rem;
    }
    
    .temat[data-temat]::after {
      font-size: 1.3rem;
    }
    
    .wzor {
      font-size: 0.9rem;
      padding: 10px;
    }
  }