/* Estilos CSS puros para una interfaz limpia, profesional y rápida */
body { 
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; 
    background-color: #e9ecef; 
    display: flex; 
    justify-content: center; 
    align-items: center; 
    height: 100vh; 
    margin: 0; 
}

.login-card { 
    background-color: #ffffff; 
    padding: 40px 30px; 
    border-radius: 10px; 
    box-shadow: 0 8px 20px rgba(0,0,0,0.1); 
    width: 100%; 
    max-width: 380px; 
}

.login-card h2 { 
    text-align: center; 
    color: #2c3e50; 
    margin-top: 0;
    margin-bottom: 25px;
    font-weight: 600;
}

.form-group { 
    margin-bottom: 20px; 
}

.form-group label { 
    display: block; 
    margin-bottom: 8px; 
    color: #495057; 
    font-size: 14px;
    font-weight: 500;
}

.form-group input { 
    width: 100%; 
    padding: 12px; 
    border: 1px solid #ced4da; 
    border-radius: 5px; 
    box-sizing: border-box; 
    font-size: 15px;
    transition: border-color 0.3s;
}

.form-group input:focus {
    border-color: #3498db;
    outline: none;
}

.btn-submit { 
    width: 100%; 
    padding: 14px; 
    background-color: #2c3e50; 
    color: white; 
    border: none; 
    border-radius: 5px; 
    cursor: pointer; 
    font-size: 16px; 
    font-weight: bold;
    transition: background-color 0.3s, transform 0.1s; 
}

.btn-submit:hover { 
    background-color: #1a252f; 
}

.btn-submit:active {
    transform: scale(0.98);
}

/* Estilo para la advertencia visual */
#warning-message { 
    color: #e74c3c; 
    font-size: 14px; 
    text-align: center; 
    margin-top: 15px; 
    display: none; 
    background-color: #fadbd8;
    padding: 10px;
    border-radius: 5px;
}