bootstrap 4 blur background code example
Example 1: image blur css
filter: blur(8px);
-webkit-filter: blur(8px);
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 ;-)