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Imagine box-shadow but for a blur effect, where the backdrop of an element is blurred around that element, gradually decreasing the blur’s strength. I came up with the idea while trying to improve the contrast of a popup over a dark area where a box-shadow for the popup won’t make much sense, design-wise. I then thought, well, what other ways might create a good contrast effect? And so suddenly, the idea of a gradual blur effect around the object came to me.
See the Pen Faded Outer Box Backdrop Blur [forked] by Yair Even Or.
It would be awesome if we had a box-blur property or perhaps some sort of blur keyword we could set on box-shadow the way we do for inset shadows. Unfortunately, CSS has no such property. But because CSS is awesome and flexible, we can still get the effect by combining a few CSS features and hack it through.