In order to make the theme look exactly like you want it you sometimes might to change some CSS.
Easiest way to get the CSS attributes to change is to use Chrome Inspector or Firebug/Firefox and right click on the element you want to change, “Inspect Element”, then maybe select a parent/child element in the markup shown (the corresponding element on the page will be highlighted), then copy the CSS to adapt to your needs.
Now you have two options to change the CSS.
You can put your changes in a child-theme (especially if you need to make markup changes in the theme’s sourcecode).
This tutorials describes best how this can be handled:
http://code.tutsplus.com/tutorials/child-themes-basics-and-creating-child-themes-in-wordpress–wp-27475 and http://code.tutsplus.com/articles/how-to-customize-your-wordpress-theme-with-a-child-theme–wp-32354
Quick hack via the Custom CSS box in the theme options. Just put your custom CSS in here and it will be attached at the bottom of the normal style CSS. Updating the theme won’t hurt this settings.