.embed-responsive-16by9{aspect-ratio:16/9}.embed-responsive-16by9::before{padding-top:56.25%}.embed-responsive-3by1{aspect-ratio:3/1}.embed-responsive-3by1::before{padding-top:33.33%}.embed-responsive-3by2{aspect-ratio:3/2}.embed-responsive-3by2::before{padding-top:66.67%}.embed-responsive-4by3{aspect-ratio:4/3}.embed-responsive-4by3::before{padding-top:75.00%}