{%- case include.ratio -%}

{%- when '21:9' -%}
  {%- assign ratio_class = 'responsive-embed-21by9' -%}
{%- when '16:9' -%}
  {%- assign ratio_class = 'responsive-embed-16by9' -%}
{%- when '4:3' -%}
  {%- assign ratio_class = 'responsive-embed-4by3' -%}
{%- when '1:1' -%}
  {%- assign ratio_class = 'responsive-embed-1by1' -%}
{%- else -%}
  {%- assign ratio_class = 'responsive-embed-16by9' -%}

{%- endcase -%}

<div class=“responsive-embed {{ ratio_class }}”>

<iframe src="{{ include.url }}" frameborder="0" allowfullscreen></iframe>

</div>