Greasy Fork is available in English.
Change font, size, width and background of a work + blacklist: hide works that contain certains tags or text, have too many tags/fandoms/relations/chapters/words and other options + fullscreen reading mode + bookmarks: save the position you stopped reading a fic + number of words for each chapter and estimated reading time
< Feedback on AO3: Fic's Style, Blacklist, Bookmarks
Can you make a screenshot of it?
Which browser and script manager are you using?
This is a minor bug, but after pressing the Full Screen button, the comment box and footer are at the top when they should be at the bottom.