Button widget styling

Hey Prot,

recently I started to rely more on Eww for browsing. I like the clean and text centric looks and also the styling you applied to the shr faces! However I have my issues with the heavy buttons. It seems you styled them according to the default Emacs theme. Do you think it would be possible to add a user option to modus to enable a different less-heavyweight styling to buttons? One could use thinner lines, subtle background etc. I looked at the modus source and there are more than ten different buttons defined, when grepping for button or :box. Maybe these different faces could also inherit from a common face. Note that there is some confusion about buttons and widget-like buttons, since links in buffers are also called buttons. The most important users of widget-like buttons seem to be eww and the customize interface. It would also be great to have a cleaner looks for the customize interface, which I use mostly for exploration via embark-export from a variable completion session. Thanks!

Daniel