.dna{
    background-image: url("../images/resources/bg-01.png");
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center;
}

.dna2{
    background-image: url("../images/resources/bg-02.png");
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center;
}

.dna3{
    background-image: url("../images/resources/bg-03.png");
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center;
}