header.major {
  margin-bottom: 1.5em;
}

/* Fixiertes technisches Hintergrund-Overlay (oben rechts) */

#main {
  position: relative;
  overflow: hidden;
  isolation: isolate;   /* wichtig: eigener Stacking-Context */
}

#main::after {
  content: "";
  position: fixed;
  top: 0;
  right: 0;

  width: 50vw;
  height: 50vh;

  background-image: url("/images/bg-tech.png");
  background-repeat: no-repeat;
  background-position: top right;
  background-size: contain;

  opacity: 0.07;
  z-index: 0;           /* nicht negativ! */
  pointer-events: none;
}

/* Content über dem Overlay */
#main > * {
  position: relative;
  z-index: 1;
}