Click the "Edit Colors and Styles Site-Wide" icon in your Control Center:

 

 

 

This takes you to the Colors & Size Manager.  Notice the "i" located to the far right of each item.  Clicking this "i" opens a window that contains an image of exactly which area of the site your changes will affect:

 

 

 

You can change colors in two ways.  If you already know the hexadecimal value of the color you want, just enter it in the field to the right of the object you want to change:

 

 

The second way to change a color is to use the color picker.  Simply click "Pick" in the color to the right of the object you wish to change and the color chart will appear.  Pick the color you want and click it:   

 

 

You can also change the attributes of the text in your site.  You can change the size and style and can also choose to BOLD, UNDERLINE or ITALICIZE the font:

 

 

When you finish making your changes, make sure to scroll to the bottom of the page and click the "Save Changes" button: