Make lightbox background blurry

[user-4'33'']

Is there a way to make the background blurry when a picture is displayed within a lightbox?

I tried to achieve this without success by clearing the background color under Lay Options > Lightbox Addon > Style and writing:

.lightbox-bg {
    background-color: transparent !important;
    filter: blur(20px);
}

What could I be missing?

Thank you as always!!

[arminunruh]

#lightbox-region{
backdrop-filter: blur(5px);
}

for backgrounds u need to use
https://developer.mozilla.org/en-US/docs/Web/CSS/backdrop-filter