zurb/foundation — pull request #4192 by meredevelopment (2014-01-20 15:26:05+00:00)
Title: Set header font-weights to 'normal' (400)

After 'Open Sans' was removed, I believe the font weights should be set back to normal/400 for headings instead of 300 which suited Open Sans. Some might argue it should be 'bold'/700 for headings as that's browsers' default.