The file that you add it to is the style.css file of your theme. It’s the only css file, you can’t miss it. Yes I would highly recommend you figure out how to setup FTP since there are tons of tutorials out there that can help you. If you make a mistake and your site crashes you can just undo whatever you did and it will instantly be back up.
For the css, you could probably make the changes without needing FTP as long as you do exactly as I say….your site won’t crash from CSS. Since you dont have line numbers in the WP editor, just do a search – ctrl + F (pc) or command + F (mac) and search for this – a { until you get to the code I added above. Then once you get there, simply change the 700 to 400 and nothing else, and you should be fine.
The bold links are pretty standard/common for most sites, it’s about making it easy for your users to differentiate whats a link and whats regular text. Of course you can easily change all of this through your css (as were doing now).
By the way, I had to send Wes an email in order to read what you wrote (since he’s a moderator), because private messages don’t show up for regular customers. They only show up for moderators, and I don’t have a moderator account like I used to (temporary). So in the future if you’re posting to a regular customer/member they won’t see what you wrote if you send it as a private message.
I create awesome sites for awesome people! Contact me if interested – ericsanchez1585@gmail.com