.embed-responsive-1by1::before{aspect-ratio:1/1}.embed-responsive-1by3::before{aspect-ratio:1/3}.embed-responsive-2by3::before{aspect-ratio:2/3}.embed-responsive-3by2::before{aspect-ratio:3/2}.embed-responsive-4by3::before{aspect-ratio:4/3}.embed-responsive-48by37::before{aspect-ratio:48/37}