:root {
    --primary: #4361ee;
    --primary-dark: #3a56d4;
    --success: #06d6a0;
    --warning: #ffd166;
    --secondary: #6c757d;
    --light: #f8f9fa;
    --dark: #212529;
    --text-light: #f8f9fa;
    --text-dark: #212529;
    --bg-light: #ffffff;
    --bg-card-light: #ffffff;
    --bg-dark: #121212;
    --bg-card-dark: #1e1e1e;
    --border-light: #e0e0e0;
    --border-dark: #333333;
    --shadow: rgba(0, 0, 0, 0.1);
    --shadow-dark: rgba(0, 0, 0, 0.3);
    --transition: all 0.3s ease;
  }

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

  body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    margin: 0;
    padding: 0;
    background: var(--bg-light);
    color: var(--text-dark);
    transition: var(--transition);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
    background: linear-gradient(135deg, #f5f7fa 0%, #e4edf5 100%);
  }

  body.dark {
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
    color: var(--text-light);
  }

  .container {
    max-width: 1200px;
    width: 100%;
    background: var(--bg-card-light);
    border-radius: 16px;
    box-shadow: 0 10px 30px var(--shadow);
    transition: var(--transition);
    overflow: hidden;
  }

  .dark .container {
    background: var(--bg-card-dark);
    box-shadow: 0 10px 30px var(--shadow-dark);
  }

  /* Header styles */
  .header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 25px;
    background: var(--primary);
    color: white;
    flex-wrap: wrap;
    gap: 15px;
  }

  .logo {
    display: flex;
    align-items: center;
    gap: 12px;
  }

  .logo-icon {
    font-size: 28px;
    background: rgba(255, 255, 255, 0.2);
    width: 48px;
    height: 48px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
  }

  .logo-text {
    font-size: 22px;
    font-weight: 700;
    letter-spacing: -0.5px;
  }

  /* File upload section */
  .upload-section {
    margin: 25px;
    position: relative;
    border-radius: 12px;
    padding: 25px;
    background: rgba(67, 97, 238, 0.05);
    border: 2px dashed rgba(67, 97, 238, 0.2);
    transition: var(--transition);
    text-align: center;
  }

  .dark .upload-section {
    background: rgba(67, 97, 238, 0.1);
    border: 2px dashed rgba(67, 97, 238, 0.3);
  }

  .upload-section.highlight-drop {
    background: rgba(67, 97, 238, 0.15);
    border-color: var(--primary);
    transform: scale(1.01);
  }

  .file-input-wrapper {
    position: relative;
    display: inline-block;
    margin-bottom: 20px;
  }

  .file-input-wrapper input[type="file"] {
    position: absolute;
    left: 0;
    top: 0;
    opacity: 0;
    width: 100%;
    height: 100%;
    cursor: pointer;
  }

  .file-input-btn {
    background: var(--primary);
    color: white;
    padding: 12px 25px;
    border-radius: 8px;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: 0 4px 12px rgba(67, 97, 238, 0.3);
  }

  .file-input-btn:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
  }

  .drop-hint {
    font-size: 16px;
    color: var(--secondary);
    margin-top: 15px;
  }

  .dark .drop-hint {
    color: #aaa;
  }

  .file-name {
    margin-top: 15px;
    font-size: 15px;
    font-weight: 500;
    padding: 10px 15px;
    background: rgba(67, 97, 238, 0.1);
    border-radius: 8px;
    display: inline-flex;
    align-items: center;
    gap: 8px;
  }

  /* Table styling */
  .table-container {
    overflow-x: auto;
    margin: 0 25px;
    border-radius: 12px;
    border: 1px solid var(--border-light);
    transition: var(--transition);
    max-height: 500px;
    overflow-y: auto;
  }

  .dark .table-container {
    border: 1px solid var(--border-dark);
  }

  table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    min-width: 600px;
  }

  th, td {
    padding: 15px;
    text-align: left;
    border-bottom: 1px solid var(--border-light);
    transition: var(--transition);
  }

  .dark th, .dark td {
    border-bottom: 1px solid var(--border-dark);
  }

  th {
    background: rgba(67, 97, 238, 0.1);
    color: var(--primary);
    font-weight: 600;
    cursor: pointer;
    position: sticky;
    top: 0;
    transition: var(--transition);
  }

  .dark th {
    background: rgba(67, 97, 238, 0.2);
  }

  th:hover {
    background: rgba(67, 97, 238, 0.15);
  }

  .dark th:hover {
    background: rgba(67, 97, 238, 0.25);
  }

  th.sort-asc::after { content: " 🔼"; }
  th.sort-desc::after { content: " 🔽"; }

  tbody tr {
    transition: var(--transition);
  }

  tbody tr:nth-child(even) {
    background: rgba(0, 0, 0, 0.02);
  }

  .dark tbody tr:nth-child(even) {
    background: rgba(255, 255, 255, 0.03);
  }

  tbody tr:hover {
    background: rgba(67, 97, 238, 0.05);
  }

  .dark tbody tr:hover {
    background: rgba(67, 97, 238, 0.1);
  }

  /* Pagination */
  .pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 25px;
    gap: 8px;
    flex-wrap: wrap;
  }

  .pagination button {
    padding: 8px 16px;
    border: none;
    background: var(--light);
    color: var(--text-dark);
    border-radius: 8px;
    cursor: pointer;
    transition: var(--transition);
    font-weight: 500;
    min-width: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
  }

  .dark .pagination button {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-light);
  }

  .pagination button:hover:not(.active):not(:disabled) {
    background: rgba(67, 97, 238, 0.1);
    color: var(--primary);
  }

  .dark .pagination button:hover:not(.active):not(:disabled) {
    background: rgba(67, 97, 238, 0.2);
  }

  .pagination button.active {
    background: var(--primary);
    color: white;
  }

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

  /* Export buttons */
  .export-section {
    margin: 25px;
    display: flex;
    justify-content: center;
    gap: 15px;
    flex-wrap: wrap;
  }

  .export-btn {
    padding: 12px 25px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: var(--transition);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  }

  .export-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 15px rgba(0, 0, 0, 0.15);
  }

  .export-btn:nth-child(1) {
    background: var(--success);
    color: white;
  }

  .export-btn:nth-child(2) {
    background: var(--warning);
    color: var(--dark);
  }

  .export-btn:nth-child(3) {
    background: var(--secondary);
    color: white;
  }

  /* Dark mode toggle */
  .theme-toggle {
    background: rgba(255, 255, 255, 0.2);
    border: none;
    border-radius: 8px;
    padding: 10px 15px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 600;
    transition: var(--transition);
    color: white;
  }

  .dark .theme-toggle {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-light);
  }

  .theme-toggle:hover {
    background: rgba(255, 255, 255, 0.3);
  }

  .dark .theme-toggle:hover {
    background: rgba(255, 255, 255, 0.15);
  }

  /* Responsive adjustments */
  @media (max-width: 768px) {
    .container {
      margin: 0;
    }
    
    .header {
      flex-direction: column;
      align-items: flex-start;
    }
    
    .logo {
      margin-bottom: 10px;
    }
    
    .logo-icon {
      width: 42px;
      height: 42px;
      font-size: 24px;
    }
    
    .logo-text {
      font-size: 20px;
    }
    
    .export-section {
      flex-direction: column;
      align-items: stretch;
    }
    
    .export-btn {
      width: 100%;
      justify-content: center;
    }
    
    th, td {
      padding: 12px 10px;
    }
    
    .upload-section, .table-container, .pagination, .export-section {
      margin: 15px;
    }
  }

  @media (max-width: 480px) {
    .pagination {
      gap: 4px;
    }
    
    .pagination button {
      padding: 6px 12px;
      min-width: 36px;
    }
    
    .file-input-btn {
      padding: 10px 20px;
    }
    
    .upload-section {
      padding: 15px;
    }
  }
 
  footer {
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    background: #363949;
    color: #f6f6f9;
    text-align: center;
    user-select: none;
  }
  
  footer span {
    font-style: italic;
    font-size: small;
    font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
    font-size: 16px;
    font-weight: 500;
  }
  
  footer span a {
    color: crimson;
  }
  
  footer span a:hover {
    text-decoration: underline;
  }
  /* Print styles */
  @media print {
    body {
      background: white !important;
      color: black !important;
      padding: 0 !important;
      margin: 0 !important;
      display: block;
    }
    
    .container {
      box-shadow: none !important;
      background: white !important;
      max-width: 100% !important;
      margin: 0 !important;
      padding: 0 !important;
    }
    
    .header, .upload-section, .pagination, .export-section, .theme-toggle, .file-input-btn, .drop-hint, .file-name {
      display: none !important;
    }
    
    .table-container {
      display: block !important;
      position: static !important;
      width: 100% !important;
      max-height: none !important;
      overflow: visible !important;
      border: none !important;
      margin: 0 !important;
      padding: 0 !important;
    }
    
    table {
      width: 100% !important;
      min-width: 100% !important;
      border-collapse: collapse !important;
      page-break-inside: auto;
    }
    
    tr {
      page-break-inside: avoid;
      page-break-after: auto;
    }
    
    th, td {
      border: 1px solid #000 !important;
      padding: 8px !important;
      background: white !important;
      color: black !important;
    }
    
    th {
      background-color: #f0f0f0 !important;
    }
  }