CSS IS AWESOME
#el {
  border-image-source: paint(wobble, deeppink);
  border-image-slice: 0 fill;
  border-width: var(--border-width);
  border-image-outset: var(--border-width);
  --border-width: 50px;
}

Note: Code adapted to Houdini from https://codepen.io/ayamflow/pen/DqfBd