All is in the title

First, just wanted to say I love this theme. I am having a problem with the style css. I want to make the post tiles larger than the post content, but in the css it is all listed as just content, thus when you change the size, it changes the post content, date and the post title. Is there a way to change that so there is a H1, H2 and H3, so all three things are independent and I can change the sizes accordingly? Thanks for the help.