Om Family - Hyperlink Text Styling

Hi Everyone

I'm using the OM template and am struggling with the limitation of body links, specifically body link colour. It's not clear for readers which text is linked due to the stroke weight of the font in that template so I wanted to style hyperlinks with an underline to make it obvious versus using a lurid colour to get the links to stand out.

I know I can manually do this but it's such a basic CSS style, I'm surprised that there are no decoration options. I'm on a personal plan and not sure I'm able to deal with a custom code injection that will operate on the global style sheet based on the way the parameters are configured in the design panel of Squarespace.

I'm wondering if anyone else has had this problem or has come up with an elegant fix? 

Appreciate any advice or pointers that anyone can offer. 

Thanks in advance.

Alex