Yes I agree with Thrope, PHP has nothing to do with this, the problem should be with you CSS, check the follwing to ping down the error
1. Make sure you have not used any in-line styles
2. make sure you have not set the font as the style for the <body> tag
3. Check to see wether you have directly wirten styles for the tags, like check wether you have wirten a style directly to <p> or <td> tag, this is a very bad practice as i see it, because you can't use the tag independent of the style, insted use a class and wirte the style to that class.
I hope this will help you to ping the problem
Happy Hunting..!