#### Ratio

#### Responsive embed video 21:9

Wrap any embed like an `<iframe>` in a parent element with `.embed-responsive` and an aspect ratio. The `.embed-responsive-item` isn’t strictly required, but we encourage it.

#### Responsive embed video 1:1

Please use class `.embed-responsive-1by1` with div.

#### Responsive embed video 16:9

Please use class `.embed-responsive-16by9` with div.

#### Responsive embed video 4:3

Please use class `.embed-responsive-4by3` with div.