You can use below five colours to change the background color of your rich-text box content:
To change your box background colours, you need to edit the box's HTML code.
For deep blue, please change "bg-success" to "bg-primary";
For light blue, please change "bg-success" to "bg-info";
For yellow, please change "bg-success" to "bg-warning";
For pink, please change "bg-success" to "bg-danger";
Bootstrap is the underlying structure that LibGuides uses for displaying its pages on the internet.
It is a structure written by developers for website users. See https://getbootstrap.com/ Its main benefit is that it provides a responsive structure for pages. This means as the size of the screen changes from small mobile to large desktop screen, the boxes in the pages can be "floated" to provide the best use of screen space.
In our LibGuides it would be great to use this as best as we can.
To colour the whole box you need to put CSS into the html
<style type="text/css">#s-lg-box-collapse-13297230 { background-color: #f2dede;}</style>
where the number is the number of the box and the colour is the one you want.