.overlap-wrap{
  position: relative;
  width: 100%;
  aspect-ratio: 4 / 3;   /* statt height:900px */
  height: auto;
  overflow: visible;
}

.img-base,
.img-top{
  position: absolute;
  inset: 0 auto auto 0;   /* Basis-Referenz oben/links */
  max-width: none;
}

.img-base{
  top: 3%; left: 4%; width: 62%; z-index: 1;
}
.img-top{
  top: 88%; left: 22%; width: 58%; z-index: 2;
}

/* Mobile: Absolut aus, normaler Fluss (stack) */
@media (max-width: 768px){
  .overlap-wrap{ aspect-ratio: auto; }
  .img-base, .img-top{
    position: static;
    width: 100%;
    max-width: 100%;
  }
  .img-top{ margin-top: .75rem; }
}