html {
  height: 100%;
  background: linear-gradient(270deg, #a24bcf, #4b79cf, #4bc5cf);
  background-size: 600% 600%;

  -webkit-animation: AnimationName 15s ease infinite;
  -moz-animation: AnimationName 15s ease infinite;
  animation: AnimationName 15s ease infinite;
}
center {
  margin-top: 15%;
}
h1 {
  font-family: monospace;
  font-size: 4rem;
  color: white;
}
img {
  width: 250px;
}
@-webkit-keyframes AnimationName {
  0%{background-position:0% 50%}
  50%{background-position:100% 50%}
  100%{background-position:0% 50%}
}
@-moz-keyframes AnimationName {
  0%{background-position:0% 50%}
  50%{background-position:100% 50%}
  100%{background-position:0% 50%}
}
@keyframes AnimationName {
  0%{background-position:0% 50%}
  50%{background-position:100% 50%}
  100%{background-position:0% 50%}
}
@media only screen and (max-width: 768px) {
  center {
    margin-top: 45%;
  }
  h1 {
    font-size: 3.2rem;
  }
}