The Compositing and Blending spec. defines different properties related to compositing and blending the backgrounds of an element or the element as a whole with its backdrop. Specifically, those are background-blend-mode, mix-blend-mode and isolation.
I think, especially the first two make sense to support.
background-blend-mode allows to apply different blending effects between the backgrounds of an element. So it goes hand in hand with the properties related to the background shorthand, which are already supported. (And note that this property is actually already supported in Gecko.)
mix-blend-mode allows to apply different blending effects onto the element itself with its backrop.
isolate puts an element into an isolated group for compositing. Though I don't know if that's actually useful in the WebVTT context.
The Compositing and Blending spec. defines different properties related to compositing and blending the backgrounds of an element or the element as a whole with its backdrop. Specifically, those are
background-blend-mode,mix-blend-modeandisolation.I think, especially the first two make sense to support.
background-blend-modeallows to apply different blending effects between the backgrounds of an element. So it goes hand in hand with the properties related to thebackgroundshorthand, which are already supported. (And note that this property is actually already supported in Gecko.)mix-blend-modeallows to apply different blending effects onto the element itself with its backrop.isolateputs an element into an isolated group for compositing. Though I don't know if that's actually useful in the WebVTT context.Sebastian