NFT components designed using html and css

I appreciate the drive and motivation I get from frontend mentor . Please I will appreciate every feedback . Also I want to ask something. In my code I wanted to hide a div using Display: None , then when I hover on it I wanted Display: block to make my div appear but unfortunately that didn't happen . But when I used Opacity:0 and then hover effect I had Opacity :1 . then it worked . Please can someone explain to me why it happened that way ? I comment it on my workspace so you can easily identify it . Thanks and I really appreciate .