White lines appearing on desktop version

Hi there, I'm getting white lines appearing on the desktop version of my site. They're not there when I'm in the editor, but show up on the published page. I've attached a screenshot. Can someone help? I want to start sending this out to potential employers soon, and obviously it doesn't look great. 
Thanks! 

That worked, thank you so so much! I had been playing with a "liquid" effect when I first started the website and I guess I didn't disable all of the instances of it. Thanks again 🙂