Font work jekyll side

Please assess and merge in THIS first.

CSS that accompanies the font and typography Merge Request here, but doesn't explicitly require it, of course.

Basically it creates a rule for

• a not-to-bold font-weight for the app name
• a slightly more legible (ie. darker) text-color-light, that is consistent with other changes in the sister commit mentioned above.

See it in effect here.