html {
  background: url("utah1.jpg");
  background-position: center;
  background-size: cover;
  background-repeat: no-repeat;
  min-height: 100%;
}
body {
  margin: 0;
  padding: 0;
}
*, *::before, *::after {
  box-sizing: border-box;
}
h1 {
  font-family: 'Arima Madurai', cursive;
  color: black;
  font-size: 4rem;
  letter-spacing: -3px;
  text-shadow: 0px 1px 1px rgba(255, 255, 255, 0.6);
  position: relative;
  z-index: 3;
}
.container {
  z-index: 1;
  position: relative;
  overflow: hidden;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 35rem;
  background-blend-mode: soft-light;
  padding: 2rem;
}
.bird {
  background-image: url(bird-cells.svg);
  background-size: auto 100%;
  width: 88px;
  height: 125px;
  will-change: background-position;
  animation-name: fly-cycle;
  animation-timing-function: steps(10);
  animation-iteration-count: infinite;
}
.bird--one {
  animation-duration: 1s;
  animation-delay: -0.5s;
}
.bird--two {
  animation-duration: 0.9s;
  animation-delay: -0.75s;
}
.bird--three {
  animation-duration: 1.25s;
  animation-delay: -0.25s;
}
.bird--four {
  animation-duration: 1.1s;
  animation-delay: -0.5s;
}
.bird-container {
  position: absolute;
  top: 20%;
  left: -7.5vw;
  transform: scale(0);
  will-change: transform;
  animation-name: fly-right-one;
  animation-timing-function: linear;
  animation-iteration-count: infinite;
}

/*@media screen and (max-width: 800px) {*/
.bird-container--one {
  animation-duration: 15s;
  animation-delay: 0s;
}
.bird-container--two {
  animation-duration: 16s;
  animation-delay: 1s;
}
.bird-container--three {
  animation-duration: 14.6s;
  animation-delay: 9.5s;
}
.bird-container--four {
  animation-duration: 16s;
  animation-delay: 10.25s;
}
/*}*/

@media screen and (min-width: 1200px) {
  .bird-container--one {
    animation-duration: 20s;
    animation-delay: 0s;
  }
  .bird-container--two {
    animation-duration: 20s;
    animation-delay: 1s;
  }
  .bird-container--three {
    animation-duration: 19.6s;
    animation-delay: 9.5s;
  }
  .bird-container--four {
    animation-duration: 21s;
    animation-delay: 10.25s;
  }
}

@media screen and (min-width: 4000px) {
  .bird-container--one {
    animation-duration: 30s;
    animation-delay: 0s;
  }
  .bird-container--two {
    animation-duration: 32s;
    animation-delay: 1s;
  }
  .bird-container--three {
    animation-duration: 30.6s;
    animation-delay: 9.5s;
  }
  .bird-container--four {
    animation-duration: 32s;
    animation-delay: 10.25s;
  }
}

@keyframes fly-cycle {
  100% {
    background-position: -900px 0;
  }
}
@keyframes fly-right-one {
  0% {
    left: -10%;
    transform: scale(0.3);
  }
  10% {
    left: 10%;
    transform: translateY(2vh) scale(0.14);
  }
  20% {
    left: 30%;
    transform: translateY(0vh) scale(0.25);
  }
  30% {
    left: 50%;
    transform: translateY(4vh) scale(0.36);
  }
  40% {
    left: 70%;
    transform: translateY(2vh) scale(0.46);
  }
  50% {
    left: 90%;
    transform: translateY(0vh) scale(0.56);
  }
  60% {
    left: 110%;
    transform: translateY(0vh) scale(0.6);
  }
  100% {
    left: 110%;
    opacity: 1;
    transform: translateY(0vh) scale(0.46);
  }
}
@keyframes fly-right-two {
  0% {
    left: -10%;
    opacity: 1;
    transform: translateY(-2vh) scale(0.35);
  }
  10% {
    left: 10%;
    transform: translateY(0vh) scale(0.24);
  }
  20% {
    left: 30%;
    transform: translateY(-4vh) scale(0.36);
  }
  30% {
    left: 50%;
    transform: translateY(1vh) scale(0.45);
  }
  40% {
    left: 70%;
    transform: translateY(-2.5vh) scale(0.5);
  }
  50% {
    left: 90%;
    transform: translateY(0vh) scale(0.45);
  }
  51% {
    left: 110%;
    transform: translateY(0vh) scale(0.35);
  }
  100% {
    left: 110%;
    transform: translateY(0vh) scale(0.25);
  }
}