Add border around todays date in calendar block

Hello, i am styling the calendar block. I would like for today's date to have a solid 1px border, however using the css below, I only see a border around the bottom and left sides, any suggestions?

.calendar-calendar tr td.today, .calendar-calendar tr.odd td.today, .calendar-calendar tr.even td.today {
background-color: transparent;
border:1px solid #000;
}