Change volume icon when media_player is muted

[mrgrlscz]

Hi Clooos! Not an issue but an improvement idea for the media_player bubble-card: The volume icon should be: mdi:volume-mute (or mdi:volume-off) when the media_player is... muted. Maybe the color could also be different (some red color i guess? or another css definition)

Idem when the volume slider is active: the left icon (controlling the mute attribute) could toggle between mdi:volume-high (basic color) and mdi:volume-mute (red color), instead of just changing color.

Is this something you can add in the future!?