index.css

@import url("https://fonts.googleapis.com/css?family=Open+Sans:800|Roboto+Condensed:700i");

body {
  width: 100%;
  min-height: 600px;
  height: 100%;
  padding: 0;
  margin: 0;
  background-color: #e4ebfd;
  overflow-x: hidden;
  overflow-y: hidden;
}
.root {
  align-items: center;
  margin: 0;
}

#starter {
  z-index: 1;
  position: absolute;
  width: 100%;
  height: 100%;
  text-align: center;
  font-family: "Roboto Condensed", sans-serif;
  font-size: 2em;
  font-weight: 600;
  cursor: pointer;
  overflow: hidden;
}
#starter .ribbon img {
  overflow: hidden;
  transform: scale(0.92);
  margin-left: -2%;
}
#starter .content {
  display: flex;
  flex-direction: row;
  align-items: center;
  justify-content: space-around;
}
.center-image {
  width: 100%;
  margin: 0;
  display: inline-block;
}
.content .logo {
  width: 27%;
  height: 27%;
  border-radius: 50%;
}

.warning {
  display: none;
}

.highlight {
  color: #394677;
  font-family: Arial, Helvetica, sans-serif;
  font-size: 30px;
  font-weight: 600;
  text-shadow: 1px;
  text-align: center;
  text-decoration: none;
}

.highlightred {
  color: #ee6464;
  font-family: Arial, Helvetica, sans-serif;
  font-size: 35px;
  font-weight: 600;
  text-shadow: 1px;
}

#scene {
  position: fixed;
  top: 50%;
  left: 50%;
  width: 1200px;
  height: 600px;
  overflow: hidden;
  margin-top: -300px;
  margin-left: -600px;
  background-color: rgb(0, 0, 0);
  box-shadow: 0 0 0 2px white inset;
}
#curtain {
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: transparent;
}

#curtain .left,
#curtain .right {
  position: absolute;
  top: 0;
  width: 50%;
  height: 100%;
  filter: brightness(180%);
  background-image: url("https://s3-us-west-2.amazonaws.com/s.cdpn.io/950358/curtain.svg");
  background-size: cover;
  background-repeat: no-repeat;
}

#curtain .left {
  left: 0;
  transform-origin: top right;
}
#curtain .right {
  left: 50%;
  transform-origin: top left;
}

.ground {
  position: absolute;
  left: 50%;
  top: 133%;
  width: 10000px;
  height: 10000px;
  margin-left: -5000px;
  border-radius: 100%;
  box-shadow: 0 0 100px 100px white;
}

h1 {
  position: absolute;
  left: 42%;
  top: 50%;
  display: block;
  width: 500px;
  height: 150px;
  margin-top: -90px;
  margin-left: -250px;
  text-align: center;
  font-family: "Open Sans", sans-serif;
  font-size: 10em;
  color: white;
  transform: scale(0.75);
  opacity: 0;
}

/* **********
  opening
********** */

#scene.expand {
  width: 140%;
  left: -20%;
  margin-left: 0;
  background-color: rgb(32, 32, 32);
  box-shadow: 0 0 0 0 white inset;
  animation-fill-mode: forwards;
  animation-name: expand-scene-horizontaly, expand-scene-verticaly;
  animation-duration: 2.5s, 1.5s;
  animation-timing-function: ease-in-out, ease-in-out;
  animation-delay: 0s, 2.5s;
  animation-iteration-count: 1, 1;
  animation-direction: normal, normal;
}

#curtain.open .left,
#curtain.open .right {
  filter: brightness(100%);
}
#curtain.open .left {
  animation-fill-mode: forwards;
  animation-name: curtain-opening, left-curtain-opening;
  animation-duration: 2s, 4s;
  animation-timing-function: ease-in-out, ease-in-out;
  animation-delay: 0s, 0s;
  animation-iteration-count: 1, 1;
  animation-direction: normal, normal;
}
#curtain.open .right {
  animation-fill-mode: forwards;
  animation-name: curtain-opening, right-curtain-opening;
  animation-duration: 2s, 4s;
  animation-timing-function: ease-in-out, ease-in-out;
  animation-delay: 0s, 0s;
  animation-iteration-count: 1, 1;
  animation-direction: normal, normal;
}

#scene.expand .ground {
  animation-fill-mode: forwards;
  animation-name: ground-rising;
  animation-duration: 6s;
  animation-timing-function: ease-out;
  animation-delay: 0s;
  animation-iteration-count: 1;
  animation-direction: normal;
}

#scene.expand h1 {
  animation-fill-mode: forwards;
  animation-name: text-zoom, text-fade-in, text-glowing;
  animation-duration: 5s, 1s, 1s;
  animation-timing-function: ease-out, ease-in-out, ease-in-out;
  animation-delay: 3s, 3s, 0s;
  animation-iteration-count: 1, 1, infinite;
  animation-direction: normal, normal, alternate;
}

.fade-out {
  animation-fill-mode: forwards;
  animation-name: fade-out;
  animation-duration: 1s;
  animation-timing-function: ease-in;
  animation-delay: 0s;
  animation-iteration-count: 1;
  animation-direction: normal;
}

/* **********
  animations
********** */

@keyframes expand-scene-horizontaly {
  /* 2.5
  s */
  from {
    width: 1200px;
    left: 50%;
    margin-left: -600px;
    background-color: rgb(0, 0, 0);
    box-shadow: 0 0 0 2px white inset;
  }
  to {
    width: 140%;
    left: -20%;
    margin-left: 0;
    background-color: rgb(32, 32, 32);
    box-shadow: 0 0 0 0 white inset;
  }
}

@keyframes expand-scene-verticaly {
  /* 1.5s */
  from {
    top: 50%;
    height: 600px;
    margin-top: -300px;
  }
  to {
    top: 0;
    height: 100%;
    margin-top: 0;
  }
}

@keyframes curtain-opening {
  /* 2s */
  from {
    filter: brightness(180%);
  }
  to {
    filter: brightness(100%);
  }
}

@keyframes left-curtain-opening {
  /* 4s */
  from {
    transform: translate(0) rotate(0) scale(1, 1);
  }
  to {
    transform: translate(-100%) rotate(20deg) scale(0, 2);
  }
}

@keyframes right-curtain-opening {
  /* 4s */
  from {
    transform: translate(0) rotate(0) scale(1, 1);
  }
  to {
    transform: translate(100%) rotate(-20deg) scale(0, 2);
  }
}

@keyframes ground-rising {
  from {
    top: 133%;
  }
  to {
    top: 105%;
  }
}

@keyframes text-zoom {
  from {
    transform: scale(0.75);
  }
  to {
    transform: scale(1);
  }
}

@keyframes text-fade-in {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

@keyframes text-glowing {
  from {
    text-shadow: 0 0 10px white;
  }
  to {
    text-shadow: 0 0 10px white, 0 0 20px white, 0 0 30px dodgerblue;
  }
}

@keyframes fade-out {
  from {
    color: black;
    opacity: 1;
  }
  to {
    color: white;
    opacity: 0;
  }
}

@media (max-width: 420px) {
  #starter {
    display: none;
  }
  .warning {
    color: red;
    position: relative;
    z-index: 2;
    align-items: center;
    display: inline;
    display: flex;
    justify-content: center;
    margin-top: 50%;
    text-align: center;
    align-items: center;
  }
}