Border radius is not working in calendar

i want border radius like above given sample in corners


Please try to add !important after border-radius property in your CSS. This will make sure that the border radius is applied even if there are conflicting styles:

.wx-event-calendar-event {
    border-radius: 12px !important;

Here is an example: DHTMLX Snippet Tool

not for event i want border radius for timeline corners


You need to style the wx-event-calendar-grid element. It should also be noted that it does not have a visible border, but I added it as an example:

div.wx-event-calendar-grid {
    border: 1px solid #4c4c4c;
    border-radius: 10px;

Please see: DHTMLX Snippet Tool