If you try to apply a class attribute like this:
void OnSecondDateRender(DateRenderEventArgs args)
{
if (_firstDateValue == null) return;
IEnumerable<DateTime> dates = [_firstDateValue.Value];
var hasHighlightedDate = dates.Select(d => d.Date).Contains(args.Date.Date);
if (hasHighlightedDate)
{
args.Attributes.Add("style", "background-color: var(--colors-primary-primary);border-radius: 4px;");
args.Attributes.Add("class","ggg");
}
}
Only the style attribute works. The class property is not added.