Change banner in Harris?

I use the Harris template and want to change the banner text to white and add the smaller font text (that is now below my logo) into the banner, i.e. have two different font sized in the banner. I cannot figure out how to do this. Anyone knows?? 

You should be able to change the text colour in the styles menu.
If you no longer want the tag line near the logo, you can remove the tag line in Design -> Logo & Title.