How to center two columns?

As you can see-

https://www.wildwanderingrrl.web44.net/wordpress/moonlight/

my attempt at using the div-tag kind of columns looks OK only I can’t see to get them to center. The left is pushing way off to the left margin although the right one doesn’t look bad. I’ve messed around with the “padding” numbers but nothing changes…

I installed the Easy Columns plugin but can’t make heads or tails out of how to use it…