.header-logo img {
  transition: opacity 0.5s ease;
}

/* Initially show black logo, hide white logo */
.header-logo img[src*="black"] {
  opacity: 1;
}

.header-logo img[src*="white"] {
  opacity: 0;
  position: absolute;
  top: 0;
  left: 0;
}


.sticky .header-logo img[src*="black"] {
  opacity: 0;
}

.sticky .header-logo img[src*="white"] {
  opacity: 1;
}