If look in to the project you’ll see I have two variants, a dark one and a white one. I hope I can keep it like that because it’s easier to build pages that way.
There are loads of hacky ways to achieve this with pure CSS using clip-paths, pseudo-elements, and/or gradients. All of which aren’t ideal, but will work. You could also use an image.
However, if you’re not comfortable with CSS, your best option may be to just drop the angled corner and try something else.