{# Embed a YouTube video #}
{% macro youtube(id, width="560", height="315") %}
{% if id is not starting_with("http") %}
{% set id = "https://www.youtube.com/embed/" ~ id %}
{% endif %}
<p><iframe width="{{width}}" height="{{height}}" src="{{id}}" title="" frameBorder="0" allow="accelerometer;" allowFullScreen></iframe></p>
{% endmacro youtube %}