.pb{
    padding-bottom: 20px;
}

.alerta{
    align-content: center; 
    text-align: center;
}

.alerta-padding{
    padding: 30px;
}

.card{
    margin-top: 20px;
}

.btn-marg{
    margin-top: 10px;
    margin-right: 5px;
}