.before_image{
    margin-bottom: 0;
}


@media (orientation: portrait){

    .img_fulldisplay{
        width: 90vw;
        border: 2px solid black; border-radius: 3vw;
    }

    #start_theory{
        height: 17vw;
    }

    #header p{
        font-size: 3.8vw;
    }

    #header .link_box{
        padding-left: 1vw; padding-right: 1vw;
        padding-top: 3vw; padding-bottom: 3vw;
    }

}