Great idea, thanks!!

That didn't work for me (because I have old computer?) so I made a bookmarklet[0]:

  javascript:(function(){var i,x=document.querySelectorAll(".commtext");for (i=0;i<x.length;i++) x[i].className='commtext c00'})();

- which works fine. I never knew an easy way of doing that, much obliged. No more straining to read super-light grey. (Maybe better to change them to some other colour instead, like red.)

[0] i.e. I made a browser bookmark named 'ungrey' with that javascript as the 'URL', and dragged it to bookmark bar.