Here I'll show you how to add filters on hover for your Thumbnails index.
You can add grayscale, blur, invert, brightness and many other filters to your default or hover states.
If you want to use this effect for a single image – check this video: • Add effects to image on hover for a C...
Other filters: https://www.w3schools.com/cssref/css3...
Check your syntax: https://validator.w3.org/nu/#textarea
Say hello: / xiu_web