I did this with CSS forever ago. Make an alpha gradient (from background color to transparent), save it as png, add an element to use the background-image on, a

I did this with CSS forever ago. Make an alpha gradient (from background color to transparent), save it as png, add an element to use the background-image on, and use absolute positioning to put it on top. Finish it with pointer-events: none Why on earth would it be a big deal not to use JS for this. Even a frost effect has been demoed in CSS. Of course nowadays you don't need the png.