How to change Page colour in Twenty Fourteen Theme

That should be something you can change in the WordPress Customizer. Have you taken a look there?

Yup, there is no option that does that. People are using codes in Styles.css but I don’t know what and where to write there. So if someone can help with the code and show me where to put it I will be more then grateful.

Ok, try adding the code below to the bottom of your style.css file:

.main-content {background: #000;}

Thanks sooooo much, now I just need to change the place where the text is to black too https://test.larp-plovdiv.org/