#mainContainer {
  height: 100vh;
}

.background {
  width: 100%;
  height: 100%;
  top: 0;
  left: 0;
  z-index: -100;
  transition: opacity 1s ease-in-out;
}

#evenPictures {
  background: linear-gradient(rgba(0, 0, 0, 0.4), rgba(0, 0, 0, 0.4)), url("../res/OBRAS/patrimoniales/Politeama/terminadas/exterior/1.jpg");
  background-size: cover;
  background-repeat: no-repeat;
}

#oddPictures {
  opacity: 0;
}

.inner {
  position: absolute;
}