The code in the theme css file is

body {
    background: #111111 url(images/bg.png);
    width: 980px;
    color: #333333;
    font-size: 12px;
    font-family: Arial, Tahoma, Verdana;
    margin: 0px auto 0px;
    padding: 0px;
    }

I want to change the post font like:



How should I change the code?
Please help.

If you just want to change the font, then find the class for posts and change the font-family.

Thank you I have fixed the problem.