.persona__img{
    width: 300px;
    height: 300px;
    margin: 0 auto;
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center;
    border-radius: 50%;
    -webkit-border-radius: 50%;
    -moz-border-radius: 50%;
    -ms-border-radius: 50%;
    -o-border-radius: 50%;
}

.persona__img--roberta{
    background-image: url("../../img/personas/roberta.jpg");
}

.persona__img--marcela{
    background-image: url("../../img/personas/marcela.jpg");
}

.persona__img--andreia{
    background-image: url("../../img/personas/andrea.jpg");
}

@media screen and (max-width: 350px) {
    .persona__img{
        width: 200px;
        height: 200px;
 
    }
}