Proofreader styling on desktop is broken in two ways.
First, in dark mode the drawer at the bottom still has a white background.
Second, when the drawer is scrolled down and a hover over a correction forces it to scroll back up again, it does not scroll far enough. In the screenshot I had scrolled down a bit, and then hovered over the portion of text that I haven't pixelated. It correctly scrolled up to the item "bignificant -> significant," but as you can see, part of that item is obscured by the drawer header.
(Also, the original text had "big," which got corrected to "significant," but because they both share the "ig" it got confused with the diff. I don't really care about that little bug, but there you have it.)
