All the colors and fonts are controlled by the InventoryStores stylesheet. 

There is typically a file called stylesheet.css in the templates folder of whatever particular template is being used. 

You can view the HTML source for the site, then search for any visible content of the page you want to know the style of.  Search for a "style = xxx" reference, then search the stylesheet for that style name.  This process assumes some basic HTML knowledge, but you can easily change the colors and styles on the entire site from this one file.