Change in typography?

Yesterday, suddenly the typography in my posts and pages changed. The fonts in the top Menu appear much bigger now (which is not a bad thing actually). Problem is I have set all my texts to grey color (#575757) and now suddenly all apears black and bold. I tried to change manually each text but it doesn’t work

Please check the difference in my live page and mirror test domain.

http://developingthebusiness.com/venta-por-referidos/ (live page, onepress childtheme)

http://www.insightselling.es/?p=465 (testing domain, onepress theme)

I didn’t touch anything before. It happened yesterday.
Can you help me please?

REgards,