Change featured content to 2 columns with different size (width)

Hi there, I am currently working on a homepage: https://umpda.rackham.umich.edu/ I already made quite some changes to the CSS but there is one thing I can not change so far. I would like to set the amount of columns in the featured contend to just 2 columns not 3 or 4. In addition I want the left column to be 2/3 of the size and the right column to be 1/3 of the size that is givin in that space. If that is not possible both columns could be in the same size. Hope you can help me out here. Would be much appreciated. Thanks in advance.