.el {
  background: var(--rough-fill);
  border: var(--rough-stroke-width) solid var(--rough-stroke);
  --rough-fill: red;
  --rough-stroke: white;
  --rough-stroke-width: 4px;
  --rough-roughness: 7;
}
@supports (border-image-source: paint(rough-boxes)) {
  .is-loaded .el {
    border-image-source: paint(rough-boxes);
    border-image-slice: 0 fill;
    border-image-outset: 10px;
    background: none;
  }
}

Note: Code adapted from Rough.js