Body Text Overlapping Background

Hi on one of my sites I’m playing around with the style sheet and trying to make the body text of the posts fit the newly created shape I built (using my header as the size) anyways, now the text is overflowing into the page’s background. Anyone know how to make the text stop at the end of the green? Here’s the page in question..

https://skipstermag.com/misc/

Thank you