body {
  opacity: 0;
  transition: opacity 0.5s ease-in-out;
  background-color: #1E2B2B; /* your teal transition colour */
}

body.fade-in {
  opacity: 1;
}

/* Fullscreen page transition overlay */
.page-transition-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: #1E2B2B; /* Your dark teal */
  z-index: 9999;
  pointer-events: none;
  opacity: 1;
  transition: opacity 0.5s ease-in-out;
}

.page-transition-overlay.fade-out {
  opacity: 0;
}