Comment 21 for bug 222256

I did some more research and found out that Epiphany apparently uses a combination of Gnome settings and fontconfig to select the appropriate font and its size for generic font families. The reason why the "serif" family looks weird in my screenshot, is because fontconfig suggests "DejaVu Serif" for it on my setup. If I create a .fonts.conf file that overrides that with "Times New Roman", it works as expected.

I could not still find a way to choose the font family used for "sans-serif" though. Anyway, this seems to be an upstream issue and a proper way to fix it IMHO, would be allow the user to override the system-wide font settings. That would be consistent with gedit, gnome-terminal and gnome help browser etc.