w3schools blur background image code example

Example 1: add blur background css

backdrop-filter: blur(5px);

Example 2: css blur background image only

// best workaround is two images layered... (one on left is on top)
background-image: url(opaque_blurred.png), url(regular_bakground_img.jpg);
// BAM! that right there is worth at least a buck donation ;-)