Username Color & Title Size

Hi. I'm new to WP, and I'm loving Your Simple Catch theme. Here's my blog: http://www.smilingheartsdiary.com I just need help with a couple of things: 1) I use a black background, and the usernames in the comments section aren't visible. How do I change to a lighter text color? http://www.smilingheartsdiary.com/2014/10/21/the-subway-cellist/ 2) How do I make smaller the title text of each blog entry? I'd appreciate your help. Is there any way to simply add code to Appearance>ThemeOptions>CustomCSS? Thanks! :)