.embed-responsive-3by4{aspect-ratio:3/4}.embed-responsive-3by4::before{padding-top:133.33%}.embed-responsive-4by3{aspect-ratio:4/3}.embed-responsive-4by3::before{padding-top:75.00%}.embed-responsive-48by31{aspect-ratio:48/31}.embed-responsive-48by31::before{padding-top:64.58%}