#main_caption{
    width: auto;
}
.link_box{
    display: block;
    margin:-800px auto 430px auto;
    padding:0;
    position: relative;
}
.link_box a{
    display: inline-block;
    width: 425px;
    height: 370px;
    margin: 0 20px;
    border-radius: 50%;

}
.link_box a:nth-child(1){}
.link_box a:nth-child(1){}

@media screen and (max-width: 800px) {
    .link_box{
        margin:-247% auto 130% auto;
    }
    .link_box a{
        display: block;
        width: 70%;
        height: 52vw;
        margin: 0 auto 4% auto;
        text-align: center;
    }
}
@media screen and (max-width: 390px) {
    .link_box{
        margin:-253% auto 130% auto;
    }
    .link_box a{
        display: block;
        width: 70%;
        height: 52vw;
        margin: 0 auto 4% auto;
        text-align: center;
    }
}