How to hide the mwc-icon-button in a template [card-mod theme]

Configuration Frontend
1

Hello,

I use the Whats App theme and would like to hide the conversation button in this theme?

According to the browser it is the following button:

image

I have added the following code at the end of the theme. However, this has no effect:

    card-mod-theme: whatsapp_theme
    card-mod-root-yaml: |
      .mwc-icon-button[label="Start conversation"] {
        display: none !important;
      }

This is how it currently looks:

      paper-toast-color: var(--primary-text-color)
      mdc-linear-progress-buffer-color: rgba(0,0,0,0.2)
      data-table-background-color: var(--wa-bg-2)
    card-mod-theme: whatsapp_theme
    card-mod-root-yaml: |
      .mwc-icon-button[label="Start conversation"] {
        display: none !important;
      }

What am I doing wrong?
Finally, the following CSS code should be added to the button:
image

I haven’t been with HA that long. Thanks a lot.
BR

2

Asking not in a dedicated thread )))

3

So should I post the same thing again in the topic you tagged?

4

This could be better.
Read this please.