*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

main{
    text-align: center;
    margin-top: 50px;
}
main img{
    width: 50%;
}
@media screen and (max-width: 768px) {
    main{
        margin-top: 0px;
    }
    main img{
        width: 100%;
    }
}