There are 2 attributes of the MiniCalendar textbox background that you can modify by checking the corresponding checkbox and setting a value (if a checkbox is unchecked, the corresponding value will be ignored).
•Shade: use this value to modify the textbox background's shade. This value is in percentage, where 100% corresponds to the full color, and 0% to white.
•Color: to edit this option select one of the list of colors contained in the current GridTemplate.
In the case of weekly bands minicalendars, most of the time you will not need to set the frame and background options. It is usually easier, and more visual, to set the desired background and frame in the GridTemplate and let the token delete each textbox if it does not correspond to the current week.