main {
    width: 35vw;
    margin-left: auto;
    margin-right: auto;
}

@media screen and (width <= 900px) {
    main {
        width: 60vw;
    }
}

@media screen and (width <= 700px) {
    main {
        width: 90vw;
    }
}

h2 {
    font-size: 2.5rem;
}