It looks like you will need to make changes to the "typography.css" file as mentioned by esmi above from line 156 to 192, but it also looks like there may be some JavaScript/jQuery being used to fade the links when you hover over them.
I looked briefly at the source code and see that multiple jQuery files are being loaded. You may want to comment those out and see what happens wqhen they don't load to narrow down what is adding the fading on the links. I didn't see anything in the jQuery files setting colors, so all of that should be in the above CSS file, but maybe I missed something.
You may want to change the following section which sets all the link colors for the whole page to see if that allows you to change anything:
a { text-decoration: none; }
a:link { color: #26a; }
a:hover { color: #000; }
a:active { color: #be261e; }
a:visited { color: #26a; }
Good luck!