:root {
            --primary: #3498db;
            --secondary: #2c3e50;
            --success: #27ae60;
            --danger: #e74c3c;
            --warning: #f39c12;
            --light: #f8f9fa;
            --dark: #343a40;
        }
        
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        
        body {
            background-color: #f5f7fa;
            color: #333;
            line-height: 1.6;
        }
        
        .container {
            width: 100%;
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 15px;
        }
        
        header {
            background: linear-gradient(135deg, var(--secondary), var(--primary));
            color: white;
            padding: 1rem 0;
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
        }
        
        .header-container {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        
        .logo {
            display: flex;
            align-items: center;
            gap: 10px;
            font-size: 1.5rem;
            font-weight: bold;
        }
        
        .logo i {
            color: #e74c3c;
        }
        
        nav ul {
            display: flex;
            list-style: none;
            gap: 20px;
        }
        
        nav a {
            color: white;
            text-decoration: none;
            padding: 5px 10px;
            border-radius: 4px;
            transition: background 0.3s;
        }
        
        nav a:hover, nav a.active {
            background: rgba(255, 255, 255, 0.1);
        }
        
        .user-actions {
            display: flex;
            align-items: center;
            gap: 15px;
        }
        
        .user-info {
            display: flex;
            align-items: center;
            gap: 8px;
        }
        
        .btn {
            padding: 8px 16px;
            border: none;
            border-radius: 4px;
            cursor: pointer;
            font-weight: 500;
            transition: all 0.3s;
        }
        
        .btn-primary {
            background-color: var(--primary);
            color: white;
        }
        
        .btn-danger {
            background-color: var(--danger);
            color: white;
        }
        
        .btn-success {
            background-color: var(--success);
            color: white;
        }
        
        .btn:hover {
            opacity: 0.9;
            transform: translateY(-2px);
        }
        
        .main-content {
            padding: 30px 0;
        }
        
        .page-title {
            margin-bottom: 20px;
            padding-bottom: 10px;
            border-bottom: 2px solid var(--primary);
            color: var(--secondary);
            display: flex;
            align-items: center;
            gap: 10px;
        }
        
        .card {
            background: white;
            border-radius: 8px;
            box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05);
            padding: 25px;
            margin-bottom: 25px;
        }
        
        .form-group {
            margin-bottom: 20px;
        }
        
        label {
            display: block;
            margin-bottom: 8px;
            font-weight: 500;
            color: var(--secondary);
        }
        
        input, select, textarea {
            width: 100%;
            padding: 12px;
            border: 1px solid #ddd;
            border-radius: 4px;
            font-size: 16px;
        }
        
        input:focus, select:focus, textarea:focus {
            outline: none;
            border-color: var(--primary);
            box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.2);
        }
        
        .form-row {
            display: flex;
            gap: 20px;
            margin-bottom: 20px;
        }
        
        .form-col {
            flex: 1;
        }
        
        .tabs {
            display: flex;
            margin-bottom: 20px;
            border-bottom: 1px solid #ddd;
        }
        
        .tab {
            padding: 12px 20px;
            cursor: pointer;
            background: #f1f1f1;
            border: 1px solid #ddd;
            border-bottom: none;
            border-radius: 5px 5px 0 0;
            margin-right: 5px;
        }
        
        .tab.active {
            background: white;
            border-bottom: 1px solid white;
            margin-bottom: -1px;
            font-weight: bold;
            color: var(--primary);
        }
        
        .tab-content {
            display: none;
        }
        
        .tab-content.active {
            display: block;
        }
        
        .dashboard-stats {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 20px;
            margin-bottom: 30px;
        }
        
        .stat-card {
            background: white;
            border-radius: 8px;
            padding: 20px;
            box-shadow: 0 4px 10px rgba(0, 0, 0, 0.05);
            text-align: center;
        }
        
        .stat-card i {
            font-size: 2.5rem;
            margin-bottom: 15px;
            color: var(--primary);
        }
        
        .stat-number {
            font-size: 2rem;
            font-weight: bold;
            margin-bottom: 5px;
            color: var(--secondary);
        }
        
        .stat-label {
            color: #666;
            font-size: 1rem;
        }
        
        .patients-table {
            width: 100%;
            border-collapse: collapse;
        }
        
        .patients-table th, 
        .patients-table td {
            padding: 12px 15px;
            text-align: left;
            border-bottom: 1px solid #ddd;
        }
        
        .patients-table th {
            background-color: #f8f9fa;
            color: var(--secondary);
            font-weight: 600;
        }
        
        .patients-table tr:hover {
            background-color: #f5f7fa;
        }
        
        .action-btn {
            padding: 6px 12px;
            margin-right: 5px;
            border: none;
            border-radius: 4px;
            cursor: pointer;
        }
        
        .btn-edit {
            background-color: #3498db;
            color: white;
        }
        
        .btn-delete {
            background-color: #e74c3c;
            color: white;
        }
        
        .alert {
            padding: 15px;
            margin-bottom: 20px;
            border-radius: 4px;
        }
        
        .alert-success {
            background-color: #d4edda;
            color: #155724;
            border: 1px solid #c3e6cb;
        }
        
        .alert-danger {
            background-color: #f8d7da;
            color: #721c24;
            border: 1px solid #f5c6cb;
        }
        
        footer {
            background-color: var(--secondary);
            color: white;
            padding: 20px 0;
            margin-top: 40px;
        }
        
        .footer-content {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        
        .login-container {
            display: flex;
            justify-content: center;
            align-items: center;
            min-height: 100vh;
            background: linear-gradient(135deg, #667eea, #764ba2);
        }
        
        .login-card {
            background: white;
            border-radius: 10px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
            width: 100%;
            max-width: 450px;
            padding: 40px;
        }
        
        .login-title {
            text-align: center;
            margin-bottom: 30px;
            color: var(--secondary);
        }
        
        .login-title i {
            color: var(--primary);
            font-size: 2.5rem;
            margin-bottom: 15px;
            display: block;
        }

        /* register forms */
        .register-container {
            display: flex;
            justify-content: center;
            align-items: center;
            min-height: 100vh;
            background: linear-gradient(135deg, #667eea, #764ba2);
        }
        
        .register-card {
            background: white;
            border-radius: 10px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
            width: 100%;
            max-width: 950px;
            padding: 40px;
        }
        
        .register-title {
            text-align: center;
            margin-bottom: 30px;
            color: var(--secondary);
        }
        
        .register-title i {
            color: var(--primary);
            font-size: 2.5rem;
            margin-bottom: 15px;
            display: block;
        }
        
        @media (max-width: 768px) {
            .form-row {
                flex-direction: column;
                gap: 0;
            }
            
            .header-container {
                flex-direction: column;
                gap: 15px;
            }
            
            nav ul {
                flex-wrap: wrap;
                justify-content: center;
            }
            
            .user-actions {
                margin-top: 10px;
            }
        }