Feature Request: blur feature

[pjebs]

It would be awesome to implement the blur feature found here: https://torchlight.dev/ "Focus Your Reader's Attention"

[metonym]

Related #256. I think it could share a similar API/function to highlighted lines. The "effect" could be a custom background color, blurring etc.

[pjebs]

https://tympanus.net/Tutorials/ItemBlur/