Transparent popup-car?

Configuration Frontend
1

I’m trying to make a popup-card transaparent but it is not working. This is what I wrote:

type: custom:popup-card
style: |
  ha-card {
    --ha-card-box-shadow: none;
    background-color: transparent;
    border-radius: none;
  }
entity: remote.big_bedroom_tv
title: Big bedroom tv
card:
  type: custom:firemote-card
  entity: remote.big_bedroom_tv
  device_family: nvidia-shield
  device_type: shield-tv-pro-2019
  compatibility_mode: default
  android_tv_remote_entity: remote.big_bedroom_tv
  app_launch_1: jellyfin
  app_launch_2: disney-plus
  app_launch_3: netflix
  app_launch_4: prime-video
  app_launch_5: youtube
  visible_name_text: Shield Big Bedroom

This is what it looks like:

image
image1152×2496 127 KB

What am I doing wrong?

2 
card_mod:
  style:
    ha-dialog$: |
      div.mdc-dialog div.mdc-dialog__surface {
        background: rgba(0,0,0,0);
      }