.embed-responsive-1by3::before{aspect-ratio:1/3}.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-48by35::before{aspect-ratio:48/35}.embed-responsive-48by37::before{aspect-ratio:48/37}