Line separator between month name and daysOfWeek

[LorenzoCutrupi]

Hi, my queestion is very simple. I want to achieve this: But currently I have this: How can I add the white horizontal line between the name of the month and the days of the week?

[RaadShariat]

You can define the TableCalendar header style by setting the headerStyle property. If you want the divider between the header and the rest of the calendar, you may specify the decoration as a BoxDecoration and set the bottom border.