The sites Claude generates by default are almost always in dark mode (no option to switch) and are difficult to read when it comes to font, font color and size choices. It's almost telling you the "author" has zero interest in user experience and doesn't care. This site is several levels above that.
Is your system set to dark mode? These days I find Claude often generates pages (like reports) with light & dark mode styles, and rightfully defaults to system preference.