CSS formatting won't display in Safari

Hello Kirupians!

I’m hoping you may have suggestions to help me to know what to change so the content will display properly in Safari.

Here is the link to the forum: http://www.professorprofits.com/forum

Here is a link to the css: http://www.professorprofits.com/forum/style.css

So far, the left (main) content displays great in FireFox, and IE but not Safari. Any ideas?