main{
    margin: 100px auto !important;
}
main ul{
    margin: 50px 0;
}
.f_num{
    font-size: 1.5rem;
    color: #333;
}
main ul li{
    color: #777;
}
.f01{
    background-image: url(/img/f01.jpg) !important;
}

@media screen and (max-width:550px) {
    .f_num{
        font-size: 1.2rem;
    }
    main ul li{
        font-size: 0.9rem;
    }
}