Browser_mod Popup Card Formatting (Redux)

Trying to discover whether formatting really can be applied to a browser_mod popup card, and if so, how?

I have an entity called All Interior Lights. When I click on that, it pops up a window giving me the list of interior lights (whose colors change depending on state) and allows me to toggle them off/on manually.

All’s good so far. But, when I try to format the popup dialog box, I seem to hit issues - I always end up with a grey box and white lettering (and that annoying orange timer count-down line). I can turn the whole box blue, or green, but other than primary colors, no combination of #hex or RGB() values seem to work.

Ideally, I’d like to be able to change to background color to a darker grey (#A9A9A9), and maybe the text to black, plus a black border to the popup to make it stand out.

The code snippet for the formatting is shown below:

    tap_action:
      action: fire-dom-event
      browser_mod:
        service: browser_mod.popup
        data:
          timeout: 10000
          card_mod:
            style:
              ha-dialog$: |
                div.mdc-dialog div.mdc-dialog__scrim {
                  background: transparent;
                }
                div.mdc-dialog {
                  backdrop-filter: blur(5px);
                  }
                div.mdc-dialog .mdc-dialog__container .mdc-dialog__surface {
                  background: #A9A9A9;  # set the background color of the popup card here
                  color: black;      # optional: adjust text color for contrast
                }

Full disclosure, I snagged the formatting code from another post, and don’t understand why the “background:” and “color:” values don’t take effect (other than the obvious “background: blue”). Sadly, I don’t even understand what the div.mdc-dialog refers to!

Is there better documentation on how to control formatting of the poopup card available, especially where all these div.mdc keywords are defined?