.alert {
    position: relative;
    padding: 1rem 1.5rem;
    border-radius: 0.5rem;
    margin-bottom: 1rem;
    font-weight: 500;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
    animation: fadeOut 4s forwards;
    transition: opacity 1s ease-out;
}

/* Estilos específicos por tipo de alerta (supondo classes do Flask ou Bootstrap) */
.alert-success {
    background: #d4edda;
    border: 1px solid #c3e6cb;
    color: #155724;
}

.alert-error, .alert-danger {
    background: #f8d7da;
    border: 1px solid #f5c6cb;
    color: #721c24;
}

.alert-warning {
    background: #fff3cd;
    border: 1px solid #ffeeba;
    color: #856404;
}

.alert-info {
    background: #d1ecf1;
    border: 1px solid #bee5eb;
    color: #0c5460;
}

@keyframes fadeOut {
    0% { opacity: 1; }
    90% { opacity: 1; }
    100% { opacity: 0; }
}