.FlexEmbed
renders 1:1
supports dynamic, inline ratios
supports max-height
supports min-height
supports max-width
supports min-width
.FlexEmbed-ratio--3by1
renders 3:1
.FlexEmbed-ratio--2by1
renders 2:1
.FlexEmbed-ratio--16by9
renders 16:9
.FlexEmbed-ratio--4by3
renders 4:3