Hi I didn’t do it that way, I set the layout of the sidebars in the theme options. I did not customize it in CSS.
To do what I did,
first go Appearance, then choose Theme options –
then choose Layout Options
Choose style 1 (3 columns).
Then go to CSS tab in theme options and paste in the code that Sakin posted on this thread.
That made the left and right sidebar equal for me. It gave me a bigger middle section than the layout option choice (style 3) which has equal left and right sidebars but the middle column gets really skinny if you use this style choice.