* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        body {
            font-family: Arial, sans-serif;
            background-color: #f0f0f0;
            padding: 20px;
        }
        .container {
            max-width: 400px;
            margin: 50px auto;
            background-color: #fff;
            padding: 30px;
            border-radius: 8px;
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
        }
        h1 {
            text-align: center;
            margin-bottom: 30px;
            color: #333;
            font-size: 24px;
        }
        .form-group {
            margin-bottom: 20px;
        }
        label {
            display: block;
            margin-bottom: 8px;
            font-weight: bold;
            color: #555;
        }
        input[type="text"],
        input[type="password"] {
            width: 100%;
            padding: 12px;
            border: 1px solid #ddd;
            border-radius: 4px;
            font-size: 16px;
        }
        input[type="text"]:focus,
        input[type="password"]:focus {
            outline: none;
            border-color: #10b981;
            box-shadow: 0 0 0 2px rgba(16, 185, 129, 0.1);
        }
        .error-message {
            background-color: #ffe6e6;
            color: #cc0000;
            padding: 10px;
            border-radius: 4px;
            margin-bottom: 20px;
            text-align: center;
        }
        .submit-btn {
            width: 100%;
            padding: 12px;
            background-color: #10b981;
            color: white;
            border: none;
            border-radius: 4px;
            font-size: 16px;
            font-weight: bold;
            cursor: pointer;
            transition: background-color 0.2s ease;
        }
        .submit-btn:hover {
            background-color: #059669;
        }
        .back-link {
            display: block;
            text-align: center;
            margin-top: 20px;
            color: #666;
            text-decoration: none;
        }
        .back-link:hover {
            color: #10b981;
        }