Troubles while trying to center pages in different browsers

Hello,

We just started a new blog by using a theme called ‘shaken grid’. Everything works great except for centering pages. Let me explain myself a little better: click this link below:
https://www.yiggler.com/2011/04/virgin_oceanic_travels/

If you see this page in Chrome or Safari the content is perfectly in the center of the page. But if you surf to the website using Firefox or Internet explorer the content is pushed to the left side of the page.

This is what is in the custom css (which works for chrome and safari)

#page{
margin: 0px auto;
width: 680px;
float: center;
clear: center;
}

If I take out one of these elements it won’t work for any browser. So My question is how can I adjust this code so it works in all browsers? (or at least the most ‘important’)

link to website: https://www.yiggler.com

We would really appreciate some help! thnx!