/* Centrado perfecto en pantalla */
        body {
            background-color: #f4f7f6;
            height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
        }
        .login-card {
            width: 100%;
            max-width: 400px;
            padding: 20px;
            border-radius: 15px;
            border: none;
        }