html,
body {
  background: linear-gradient(45deg, #2d2d2d 9%, black 100%);
  width: 100%;
  height: 100%;
  overflow: hidden;
}

h1 {
  font-family: 'CoreCircus', sans-serif;
  font-size: 14vw;
  text-align: center;
  line-height: 1;
  margin: 0;
  top: 50%;
  left: 50%;
  -webkit-transform: translate(-50%, -50%);
          transform: translate(-50%, -50%);
  position: absolute;
  color: #2d2d2d;
  letter-spacing: -.5rem;
}

h1:before {
  content: attr(data-heading);
  position: absolute;
  overflow: hidden;
  color: #ff3300;
  width: 100%;
  z-index: 5;
  text-shadow: none;
  left: 34%;
  text-align: left;
  -webkit-animation: flicker 3s linear infinite;
          animation: flicker 3s linear infinite;
}

@-webkit-keyframes flicker {
  0%, 19.999%, 22%, 62.999%, 64%, 64.999%, 70%, 100% {
    opacity: .99;
    text-shadow: -1px -1px 0 rgba(255, 255, 255, 0.2), 1px -1px 0 rgba(255, 255, 255, 0.2), -1px 1px 0 rgba(255, 255, 255, 0.2), 1px 1px 0 rgba(255, 255, 255, 0.2), 0 -2px 8px, 0 0 2px, 0 0 5px #ff7e00, 0 0 15px #ff4444, 0 0 2px #ff7e00, 0 2px 3px #000;
  }
  20%, 21.999%, 63%, 63.999%, 65%, 69.999% {
    opacity: 0.4;
    text-shadow: none;
  }
}

@keyframes flicker {
  0%, 19.999%, 22%, 62.999%, 64%, 64.999%, 70%, 100% {
    opacity: .99;
    text-shadow: -1px -1px 0 rgba(255, 255, 255, 0.2), 1px -1px 0 rgba(255, 255, 255, 0.2), -1px 1px 0 rgba(255, 255, 255, 0.2), 1px 1px 0 rgba(255, 255, 255, 0.2), 0 -2px 8px, 0 0 2px, 0 0 5px #ff7e00, 0 0 15px #ff4444, 0 0 2px #ff7e00, 0 2px 3px #000;
  }
  20%, 21.999%, 63%, 63.999%, 65%, 69.999% {
    opacity: 0.4;
    text-shadow: none;
  }
}