Help with website HTML coding

We have a Boldgrid account for our business and we are in the process of editing the Materialis theme. The Materialis theme has a set typography and we have been able to edit the font in our pages, but I had to install the Collapso-o-matic plug in and use a shortcode to add a collapse button for text. That worked great. The issue I am having is that the font style, color and size is not what I want and does not match the website font. I need a walk-through for this one project and possibly for more projects on an as needed basis. The code from Collapse-O-Matic is: [expand title="trigger text"]hidden content[/expand] My customized code is : [expand title="Bio"]John is bringing us more than 30 years of successful strategic technology innovation, project management, and business leadership experience.[/expand]