:root {
      --primary: #4361ee;
      --secondary: #3f37c9;
      --success: #4cc9f0;
      --danger: #f72585;
      --light: #f8f9fa;
      --dark: #212529;
      --border-radius: 12px;
      --box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
      --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
    }
    
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    
    body {
      font-family: 'Poppins', sans-serif;
      background-color: #f5f7ff;
      min-height: 100vh;
      color: var(--dark);
    }
    
    /* Header/Nav */
    .app-header {
      background: linear-gradient(135deg, var(--primary), var(--secondary));
      color: white;
      padding: 1rem 2rem;
      box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
      position: relative;
    }
    
    .app-title {
      font-size: 1.5rem;
      font-weight: 600;
      display: flex;
      align-items: center;
      gap: 10px;
    }
    
    .app-title i {
      font-size: 1.8rem;
    }
    
    .logout-btn {
      position: absolute;
      right: 2rem;
      top: 50%;
      transform: translateY(-50%);
      background: rgba(255, 255, 255, 0.2);
      border: none;
      color: white;
      padding: 0.5rem 1.2rem;
      border-radius: 50px;
      font-weight: 500;
      cursor: pointer;
      display: flex;
      align-items: center;
      gap: 8px;
      transition: var(--transition);
      display: none;
    }
    
    .logout-btn:hover {
      background: rgba(255, 255, 255, 0.3);
    }
    
    /* Main Container */
    .main-container {
      max-width: 1200px;
      margin: 2rem auto;
      padding: 0 1rem;
    }
    
    /* Login Card */
    .auth-card {
      background: white;
      border-radius: var(--border-radius);
      box-shadow: var(--box-shadow);
      padding: 2.5rem;
      max-width: 500px;
      margin: 3rem auto;
      text-align: center;
    }
    
    .auth-card h2 {
      margin-bottom: 1.5rem;
      color: var(--primary);
      font-size: 1.8rem;
    }
    
    .form-group {
      margin-bottom: 1.5rem;
      text-align: left;
    }
    
    .form-group label {
      display: block;
      margin-bottom: 0.5rem;
      font-weight: 500;
      color: #555;
    }
    
    .form-control {
      width: 100%;
      padding: 0.8rem 1rem;
      border: 1px solid #ddd;
      border-radius: var(--border-radius);
      font-size: 1rem;
      transition: var(--transition);
    }
    
    .form-control:focus {
      border-color: var(--primary);
      box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.2);
      outline: none;
    }
    
    .btn {
      display: inline-block;
      padding: 0.8rem 1.5rem;
      border-radius: var(--border-radius);
      font-weight: 600;
      cursor: pointer;
      transition: var(--transition);
      border: none;
      font-size: 1rem;
    }
    
    .btn-primary {
      background: var(--primary);
      color: white;
      width: 100%;
    }
    
    .btn-primary:hover {
      background: var(--secondary);
      transform: translateY(-2px);
    }
    
    .error-msg {
      color: var(--danger);
      font-size: 0.9rem;
      margin-top: 0.5rem;
      text-align: center;
    }
    
    /* Dashboard */
    .dashboard {
      display: none;
      background: white;
      border-radius: var(--border-radius);
      box-shadow: var(--box-shadow);
      overflow: hidden;
      margin-bottom: 2rem;
    }
    
    .dashboard-header {
      background: linear-gradient(135deg, var(--primary), var(--secondary));
      color: white;
      padding: 1.5rem 2rem;
    }
    
    .dashboard-header h2 {
      font-size: 1.5rem;
      margin-bottom: 0.5rem;
    }
    
    .user-info {
      display: flex;
      flex-wrap: wrap;
      gap: 1.5rem;
      margin-top: 1rem;
    }
    
    .info-item {
      flex: 1;
      min-width: 200px;
    }
    
    .info-label {
      font-size: 0.9rem;
      opacity: 0.8;
    }
    
    .info-value {
      font-weight: 500;
      margin-top: 0.3rem;
    }
    
    /* Dashboard Tabs */
    .tab-nav {
      display: flex;
      background: #f8f9fa;
      border-bottom: 1px solid #eee;
      padding: 0 1rem;
    }
    
    .tab-btn {
      padding: 1rem 1.5rem;
      background: none;
      border: none;
      font-weight: 500;
      color: #666;
      cursor: pointer;
      position: relative;
      transition: var(--transition);
    }
    
    .tab-btn.active {
      color: var(--primary);
    }
    
    .tab-btn.active:after {
      content: '';
      position: absolute;
      bottom: -1px;
      left: 0;
      width: 100%;
      height: 3px;
      background: var(--primary);
    }
    
    .tab-content {
      padding: 2rem;
    }
    
    .tab-pane {
      display: none;
    }
    
    .tab-pane.active {
      display: block;
      animation: fadeIn 0.3s ease;
    }
    
    @keyframes fadeIn {
      from { opacity: 0; transform: translateY(10px); }
      to { opacity: 1; transform: translateY(0); }
    }
    
    /* Student Cards */
    .student-cards {
      display: grid;
      grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
      gap: 1.5rem;
      margin-top: 2rem;
    }
    
    .student-card {
      background: white;
      border-radius: var(--border-radius);
      box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
      padding: 1.5rem;
      border: 1px solid #eee;
      transition: var(--transition);
    }
    
    .student-card:hover {
      transform: translateY(-5px);
      box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
    }
    
    .student-card h3 {
      color: var(--primary);
      margin-bottom: 1rem;
      display: flex;
      align-items: center;
      gap: 10px;
    }
    
    .student-card h3 i {
      font-size: 1.2rem;
    }
    
    .student-info {
      margin-top: 1rem;
    }
    
    .student-info p {
      margin-bottom: 0.5rem;
      display: flex;
      justify-content: space-between;
    }
    
    .student-info span:first-child {
      font-weight: 500;
      color: #555;
    }
    
    /* Route Info */
    .route-form {
      display: flex;
      gap: 1rem;
      margin-bottom: 1.5rem;
    }
    
    .route-form .form-control {
      flex: 1;
    }
    
    .route-result {
      background: #f8f9fa;
      border-radius: var(--border-radius);
      padding: 1.5rem;
      margin-top: 1.5rem;
      border: 1px dashed #ddd;
    }
    
    /* File Upload */
    .file-upload {
      margin-top: 1.5rem;
    }
    
    .file-upload-label {
      display: block;
      margin-bottom: 1rem;
      font-weight: 500;
    }
    
    .file-input {
      width: 100%;
      padding: 1rem;
      border: 2px dashed #ddd;
      border-radius: var(--border-radius);
      text-align: center;
      cursor: pointer;
      transition: var(--transition);
      margin-bottom: 1rem;
    }
    
    .file-input:hover {
      border-color: var(--primary);
    }
    
    .info-msg {
      margin-top: 1rem;
      padding: 0.8rem;
      border-radius: var(--border-radius);
      background: #e9f7ef;
      color: #28a745;
      font-size: 0.9rem;
    }
    
    /* Responsive */
    @media (max-width: 768px) {
      .auth-card {
        padding: 1.5rem;
      }
      
      .user-info {
        flex-direction: column;
        gap: 0.5rem;
      }
      
      .tab-nav {
        overflow-x: auto;
        white-space: nowrap;
        padding-bottom: 5px;
      }
      
      .route-form {
        flex-direction: column;
      }
    }