.embed-responsive-1by3::before{aspect-ratio:1/3}.embed-responsive-16by13::before{aspect-ratio:16/13}.embed-responsive-16by9::before{aspect-ratio:16/9}.embed-responsive-3by2::before{aspect-ratio:3/2}.embed-responsive-37by48::before{aspect-ratio:37/48}.embed-responsive-4by3::before{aspect-ratio:4/3}.embed-responsive-48by31::before{aspect-ratio:48/31}