How could i add gradient blur in the borders tell me plzzz or make it on your playground plzzz

Question

https://code.sololearn.com/W6Uw464ddmfy/?ref=app

Answer 1

Here:
https://ru.stackoverflow.com/questions/1221518/%D0%BA%D0%B0%D0%BA-%D1%81%D0%B4%D0%B5%D0%BB%D0%B0%D1%82%D1%8C-%D0%93%D1%80%D0%B0%D0%B4%D0%B8%D0%B5%D0%BD%D1%82%D0%BD%D0%BE%D0%B5-%D0%A0%D0%B0%D0%B7%D0%BC%D1%8B%D1%82%D0%B8%D0%B5-css3

Answer 2

Bro in which language this site is i only know english and hindi