Include a "yellow background + red border" section in a waiver content

Use the 'source' mode to open the HTML version

To create a  "yellow background + red border" section, 
just add class="yellow-bckg-red-border" into the opening tag of every element you want to be red-bordered with a yellow background.
Eg, the regular:
<div>THIS IS MY IMPORTANT CONTENT</div>

WILL BE

<div  class="yellow-bckg-red-border">THIS IS MY IMPORTANT CONTENT</div>