@guy.shachar76: You have posted your question in wrong thread and it’s not related. Also this forum is for Catch Everest theme and you are using Catch Base Pro theme. For Catch Base Pro theme, you need to post in http://catchthemes.com/support-forum/forum/catch-base-pro-premium/. From next time, please post in there.
If you just want to change font size for content area then you can change the font-size in the following css and add it in “Appearance => Customize => Theme Options => Custom CSS Options” box:
#content,
#content button,
#content input,
#content select,
#content textarea {
font-size: 15px;
}