Issue with sidebar (Footer 3 Columns instead of 4)

hello
I use 3 columns in footer and want to center them. I do this when i change the .container .four.columns { width: 220px; } into skeleton.css to 290px, and its working.
But another problem is comming after this change, it places the sidebar from right to bootom of the page. How can i center the footer 3 columns in diffrent way?
thanks