Sticky styling

I hope this is the right place to put this!

The site I'm setting up is here: http://www.safelist.com/blog/ At the moment I've got the first 3 blog posts stickied, and I notice each one is smaller (widthwise) than the one above it - and that if I make an unstickied post, the spacing between it and stickied posts are different.

I'd like post size and spacing to be the same regardless of whether they're stickied or not. Any ideas?

Thanks in advance for your help!