Adjusting Colors on Pages

I’m new to Responsive Theme so please bear with me: I would like to know how color adjustments are made on site pages, including site title and tagline. I would also like to adjust my homepage image to show all the way across, instead of two distinct areas. In short I would like my homepage to resemble this one of your showcase sites: https://www.xshadyside.com/
It just seems the needed adjustments are not available in my theme options. my URL : https://www.michaeloart.com Any help would be greatly appreciated.