Calender-Ajax

<ajaxToolkit:Calendar runat="server"
    TargetControlID="Date1"
    CssClass="ClassName"
    Format="MMMM d, yyyy"
    PopupButtonID="Image1" />


Calander theme:

.MyCalendar .ajax__calendar_container {
    border:1px solid #646464;
    background-color: lemonchiffon;
    color: red;
}