.background {
  -webkit-animation: filter-animation 10s infinite;
  animation: filter-animation 10s infinite;
  background-image: url(../img/sunset.jpg);
  background-size: cover;
  background-position: 50% 50%;
  background-repeat: no-repeat;
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
  width: 100%;
  z-index: 1;
}

.logo {
  background-image: url(../img/logo.png);
  background-position: center;
  background-repeat: no-repeat;
  background-size: 400px;
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
  width: 100%;
  z-index: 2;
}

@keyframes filter-animation {
  0% {
    filter: brightness(0.5) sepia(0.5) saturate(0.5);
  }

  10% {
    filter: brightness(0.75) sepia(0.25) saturate(1.5);
  }

  50% {
	filter: brightness(1) sepia(0) saturate(2);
  }

  70% {
    filter: brightness(0.75) sepia(0.25) saturate(1.5);
  }

  100% {
    filter: brightness(0.5) sepia(0.5) saturate(0.5);
  }
}