changing color of link text

I love this theme, but I have run into a problem. The text at the top must be lighter to been seen on the darker background (where the header text is) however, there is no option to change the link color as it currently is the same as the header text. I need to change it to be darker in the actual body of the website. You can see an example here.

https://www.steppingstonestocrystalbasics.com/authored-books/

The header text that says Stepping Stones to Crystal basics, the tag line and the primary menu are perfect.

However, if you scroll down to the body of the page, the link information is very very light. I would like that to be a darker purple.

Can that be done? if so, how? I am not a code kinda gal, but I do know how to copy and paste into CSS…….help?

thank you!