CSS to make triangle separators not working

Hello,

I am using Pagelines DMS, and I came across as website that allowed me to add CSS Triangles separators which I found here: https://iheartpagelines.com/creating-the-big-triangle-separator/

However when using this, the CSS goes off the page and creates a scrollbar along the bottom of the website. I applied the Custom CSS class to a canvas area, but it does state to apply it to a container, and I'm not sure if this has anything to do with it not working.