With the same tool that my colleague mentioned I checked the code and found out that it is used the Text element:
Now there are options available in X > Theme Options > Renew and X > Theem Options > Typography to set the characteristics of overal text.
But each element used can have a separate color and stuff. So please check the Text element article to know more on how to change the color of the text without CSS.
I suggest that you Bookmark this page which is our Knowledgebase and lists all the helpful content, try to start from the getting started section.
I also encourage you to read the Cornerstone/Content Builder section which will give you an idea about how to lay stuff on the page.
So generally what I am asking is that you first take your time and do the research and learn different stuff and then if you need our help we will be more than happy to help.