How to make Card title dynamic

It's true that the titles are plain text, but you can do some really cool stuff with the summary numbers.  it can take some cajoling, so I am providing a sample that I have verified works.  

Friends and I have found that tect must be concatenated for it to work, even if only one value is present in the concatenation.  I think it also needs to be part of a case statement.  Basically, the beast mode you create will show up as an option as a summary number if it is set up right.  

(CASE when
min(`Event_Time`) = max(`Event_Time`)
then DATE_FORMAT(MAX(`Event_Time`),'%b %Y')
else concat('Invalid selection, please select only one month at a time')
end)

You can also use colors!

***Note - The color will not render until you save and close.  

(CASE when
min(`Event_Time`) = max(`Event_Time`)
then DATE_FORMAT(MAX(`Event_Time`),'%b %Y')
else concat('<div style="color:#FF0000"<p>','Invalid selection, please select only one month at a time','</div>')
end)