Font Colors and Social Media Icons Help

Hello! I am loving this theme and cant wait to get it finished and published. Thanks for the great work!

I customized my site with a dark background graphic and since the main body is transparent I couldnt see the dark grey text so I changed it to white. Almost worked. Now the blog post preview boxes on the front page are white background with white font. I would the main post font to be white and the preview boxes font to be black like at this page….https://www.gametacularnews.com/ but how? If its in the css I need to be pointed in the right direction please.

Also, how can I make the links from the Social Media icons open in a new window?

Thank you!