How to add pricing tables in Hugo

I am atempting to add a pricing table to my Hugo blog. I read over shortcodes post on Hugo’s documentation page. I left that article knowing how to add pure html to my post.

The problem is that pricing tables (at least the ones I founds) require some html, css, and javascript. The simplest implementation I could find was here (w2school).

I should be able to get the html to work, but I am not sure where to put the css needed for this table.

The specific theme I am using is Ananke. (github link to theme)

Where should I put the css needed to get my pricing table to work?

See the Custom CSS part of the README: