How to make block borders blurry?

Question

css

Hello.

How can such an effect be achieved?
Fixed-width block, inside an unlimited number of buttons that can be scrolled through.

Answer 1

This is not a blur, but a transition to transparency.
It will help:
1. linear-gradient - if you are satisfied with making only the background of the image transparent.
2. svg mask - if you need to make it into a tight fit, as in a piccha, taking the text into transparency as well.

Answer 2

Add a pseudo element, position it in the bottom right corner, then add a drop shadow for it.