There are two CSS files in each theme folder. The "scrptcal.css" provides the styles for displaying the calendar in the browser. The "scprint.css" provides styles for printing the calendar. The classnames inside both style sheets are the same since they both refer to the same elements.
The scprint.css is included on the scrptcal.htm file with the attribute media="print". The scrptcal.css has media="sreen". This makes the scprint.css applicable when printing.
The "scprint.css" that is included in the zip displays most elements with a white background and black text. It also places a border around each weekday element. Please edit the file to print the calendar as you see fit.