How to change the font & size of a tumblr post.?

I want to change the font + size on my post titles. Because i dislike the font %26amp; the size of it. I can't seem to find the css code for it ]: I need help ):

here is my css code ..

here is my tumblr page: http://chococrap.tumblr.com/How to change the font %26amp; size of a tumblr post.?
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