.hero {
  position: relative;
  min-height: min(90vh, 1100px);
  /* ... other styles ... */
  
  /* THIS IS THE PERMANENT FIX:
    The path starts with a "/", making it root-relative.
  */
  background-image:
    linear-gradient(to top, rgba(0,0,0,.55), rgba(0,0,0,.15)),
    url("/assets/images/brand/tutu-hero-bg.webp");

  background-size: cover;
  background-position: center;
}