Playhead animation

[SuibianP]

I am making a karaoke-style subtitle and want to change the text color at playhead. :past and :future selectors only apply at text node boundaries, and the style changes word by word without animation.

#424 indicates that CSS animations are unlikely to be supported for WebVTT, and react-vttseems to be bypassing browser implementation (https://github.com/ChineseCubes/react-vtt/blob/a221ebf1fd81e306aa04f47028d26959ca7592ac/examples/demo/src/main.ls#L62, demo: http://dinamostandards.com).

However, as this is a common enough requirement for karaokes and paint-on captions, I wonder if there is any trivial workaround I am overlooking.