5
CSS variables go through from the shadow host to the elements inside. So you can do stuff like this:
.tab-audio-button[muted]{
--my-custom-image: url("muted.png");
}
.tab-audio-button[soundplaying]{
--my-custom-image: url("sound.png");
}
.button-background{
background-image: var(--my-custom-image) !important;
}