CalendarExtender cuts off the last day column

Greeting.

I use CalendarExtender. The popup calendar shows up ok in the big monitor, but not in my laptop. It shows as:

The last day column is cut off so the display is incomplete. After a bit of research, I know that it is related to the style. According to this article Skinning model for Calendar and Tabs in Ajax Control Toolkit, I think I should adjust the width in .ajax__calendar_body as: 

<style type="text/css">
        .ajax__calendar .ajax__claendar_body
        {
            width:300px;
        }</style>

Please note that I just want to make it wide enough to show the last day column. I want to keep the other formatting - including the days in previous month and next month to be of different color. (The days in November - 27 to 30 - are in gray. The days in December - 1, 2 and the rest - are in black.)

Of course, I have the CalendarExtender to use this ajax__calendar css. However it does not work. Please help.