Formatting Header Row in Chart Card

I've seen a few cards detailing how to do conditional formatting but how do you limit your formatting to only the header row. I see no reason to highlight an entire page when I want to use color coding to make it easier for me to direct how the card should be used. I'd like to highlight one column header to indicate that they should use this for drilling down and any other column headers to indicate that there is a url click out functionality on that column.