Volume control when casting audio file through Brave

When I cast an audio file from my computer to my Chromecast Audio using Brave, I can’t adjust the volume using the volume button on my laptop.
On top of that, the volume slider in Brave is so short compared to the progress bar that it’s difficult to adjust the volume precisely.

It would be cool to either be able to control the volume using the keyboard or laptop button or at least make the volume slider longer.