If you too hate the white controls in the default Google Chrome & Opera HTML5 Video Player then you're in the right place. This script makes the controls bar dark with little transparency like how it should have been.
It doesn't make sense to install this script in browsers other than chromium-based ones.
|Default HTML5 Video Player in pre-Chrome 67||Controls bar after using this script|
As of Chrome 67, the design for Native Media Controls has changed. To enable the old style head over to:
chrome://flags/#enable-modern-media-controls and set New Media Controls to Disabled