Unwanted vertical white stripe on the right

On my website, I have placed full page-width images and a colored footer that also spans the page width.  However, when I scroll to the right of the page, there is a white stripe/margin space on the right that was originally out of view.  Does anyone know why this extra space is on the website, and how to remove it?

Try adidng this code to Home > Design > Custom CSS

html, body {overflow-x: hidden;}