Blur Backdrop

Create a beautiful blur backdrop effect

blur-backdrop.css

/* From Josh Comeau's Next-level frosted glass with backdrop-filter blog:
 * https://www.joshwcomeau.com/css/backdrop-filter/
*/

.container {
  --transparent-background: color-mix(
    in oklch,
    var(--surface-3) 10%,
    transparent
  );

  position: sticky;
  inset: 0;
  inline-size: 100%;
  display: flex;
  flex-flow: row wrap;
  justify-content: center;
  gap: var(--size-3);
  z-index: calc(var(--layer-important) - 1);
  padding-block: var(--size-3);
}

.backdrop {
  position: absolute;
  inset: 0;
  block-size: 200%;
  background: var(--transparent-background);
  pointer-events: none;
  backdrop-filter: blur(var(--size-3));
  mask-image: linear-gradient(to bottom, black 0, black 50%, transparent 50%);
}

.backdrop-edge {
  /* Set this to whatever you want for the edge thickness: */
  --thickness: var(--size-1);

  position: absolute;
  inset: 0;

  /*
      Only a few pixels will be visible, but we’ll
      set the height by 100% to include nearby elements.
    */
  block-size: 100%;

  /*
      Shift down by 100% of its own height, so that the
      edge stacks underneath the main <header>:
    */
  transform: translateY(100%);
  background: var(--transparent-background);
  backdrop-filter: blur(var(--size-2)) brightness(120%);
  pointer-events: none;

  /*
      We mask out everything aside from the first few
      pixels, specified by the --thickness variable:
    */
  mask-image: linear-gradient(
    to bottom,
    black 0,
    black var(--thickness),
    transparent var(--thickness)
  );
}