The filter property applies graphical effects such as blur, brightness, contrast, grayscale, and color shifts to an element before it is rendered. You can list several filter functions in one declaration and they are applied in the order written.
Use filter: blur(5px), where the length value sets the radius of the Gaussian blur. A larger value produces a stronger blur, and 0 (or omitting the function) leaves the element sharp.
drop-shadow() follows the actual alpha shape of the content, including transparent PNGs and irregular edges, while box-shadow always draws a rectangle around the element's border box. Drop-shadow also does not support the inset or spread values that box-shadow has.
The filter property is supported in all modern browsers, including Chrome, Edge, Firefox, and Safari. Older WebKit builds needed the -webkit-filter prefix, but the unprefixed property is now safe to use without it.