Creating Columns within Text Box

Hi there! I would like to create columns within a text box so that whenever I need to add or remove text I can just do it within one block instead of having to rearranging several of them. I have a code right now but it makes the text style be one of my heading styles and I'm unable to change it. I would like the text to use the page's normal text style. Is anyone able to provide help or some code? Thank you very much, it is much appreciated! 

Thirty Eight Visuals has a great post on how to achieve this using Custom CSS: https://thirtyeightvisuals.com/blog/multicolumn-text-squarespace