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                <div>Blurred border box with the backdrop-filter + a single pseudo approach. Doesn't work in Firefox (no backdrop-filter support) or in Edge (no mask support). Needs the Experimental Web Platform features flag enabled in chrome://flags in order to work in Chrome.</div>


                $url: url(;
$b: 1.5em; // border-width

div {
	position: relative;
	padding: calc(1em + #{$b});
	max-width: 23em;
	background: $url 50%/ cover;
	color: #fff;
	font: 600 1.5em/ 1.375 segoe script, comic sans ms, cursive;
	text-shadow: 1px 1px #000;
	&:before {
		position: absolute;
		/* zero all offsets */
		top: 0; right: 0; bottom: 0; left: 0;
		border: solid $b transparent;
		background: rgba(#000, .03);
		/* doesn't work in Firefox */
		backdrop-filter: blur(9px);
		/* doesn't work in Edge */
		--fill: linear-gradient(red, red);
		-webkit-mask: var(--fill) padding-box, 
		-webkit-mask-composite: xor;
						mask: var(--fill) padding-box exclude, 
		content: ''