Visually distinguish space availability

Hi,

is there any way I could let users know visually if the event is full or if there are still places available? For example, the entire row in the event list would be coloured red if there are no more spaces. Or in the calendar (using the WP fullcalendar plugin), cells with unavailable spaces would be coloured red otherwise green.

Are there any CSS classes generated based on this requirement? Or could I generate it somehow?

Thank you