User Agent: Mozilla/5.0 (X11; Fedora; Linux x86_64; rv:57.0) Gecko/20100101 Firefox/57.0 Build ID: 20171113102334 Steps to reproduce: I am on on Gnome 3, and am using a dark GTK3 desktop theme (Adwaita Dark). When using this theme (or presumably, any dark theme), the text in the Search bar is dark on a dark background, making it nearly unreadable. This happens on any page the Search bar is displayed on (the new about:newtab, the old about:home, etc), but not to the search bar that can be placed on the browser chrome. Note that this problem goes away as soon as a light desktop theme is chosen (like the non-dark Adwaita). What is probably happening is that the Search bar's input field is getting its background colour from GTK3, but is using a hard-coded dark colour for its text/foreground. Actual results: The input field of the Search bar has dark text on a dark background. Expected results: The input field should either have light text on a dark background to match the desktop theme, or dark text on a light background to match the colour scheming of the rest of whatever page it is on, as well as the drop-down of search results (which appear with a light-on-dark colour scheme).