.watermark {
  position: fixed;
  z-index: 0;
  right: 5vw;
  top: 50%;
  width: min(31vw, 390px);
  aspect-ratio: 642 / 1147;
  pointer-events: none;
  background: url("assets/odbo-watermark.png") center / contain no-repeat;
  filter: grayscale(1) invert(1);
  opacity: .055;
  transform: translateY(-50%);
}

main { position: relative; z-index: 1; }
.sidebar { z-index: 2; }

@media (max-width: 900px) {
  .watermark { width: 46vw; right: 7vw; opacity: .04; }
}