Need help using card-mod to change header

I just installed card-mod. I am trying to use it to modify headers on a dashboard. Just to see if it works, I tried to add it to the existing yaml for the header card like so:

card:
  type: markdown
  text_only: true
  content: Climate
  card_mod: null
  style: |
    ha-card { 
      --primary-text-color: red;
    }

There were no errors or anything but the text color did not change. What am I doing wrong?

This works for me.

type: markdown
text_only: true
content: Climate
card_mod:
  style: |
    ha-card {    
    color: red;
    }
1 Like