how to make volume control fill the extra control bar width?

[JustinWebDev]

I have a div wrapper with width 300px for my audio element, which creates excess control bar space on the right end. How can I make the volume control width increase to fill this extra space? An can manually style the element with a discrete pixel adjustment, but I'd rather it just fit.

I also have media-volume-range {--_media-range-padding: 0;} set because the space between the mute button and slider was too much.