Css grid, hover effect and customization

Hey there 😊 This is was a good challenge for practicing grid though my solution have a little bug which I couldn't figure it out, grid container have a different background color at first and it slowly changes to normal but when I run this on my local machine there is no such a bug, well that's a little weird. I would appreciate it if anyone could help me.😀 btw, this one was inspired by : https://www.frontendmentor.io/profile/correlucas