html {
  font-family: sans-serif;
}

main {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -ms-flex-flow: row nowrap;
      flex-flow: row nowrap;
}

.dizzy {
  -webkit-box-flex: 0;
      -ms-flex: 0 1 10em;
          flex: 0 1 10em;

  padding: 1em;
  background-color: pink;
  text-align: right;

  -webkit-animation-name: wobble;

          animation-name: wobble;
  -webkit-animation-duration: 750ms;
          animation-duration: 750ms;
  -webkit-animation-direction: alternate;
          animation-direction: alternate;
  -webkit-animation-timing-function: ease-in-out;
          animation-timing-function: ease-in-out;
  -webkit-animation-iteration-count: infinite;
          animation-iteration-count: infinite;
}

@-webkit-keyframes wobble {
  0% {
    flex-basis: 20em;
  }
  100% {
    flex-basis: 10em;
  }
}

@keyframes wobble {
  0% {
    -ms-flex-preferred-size: 20em;
        flex-basis: 20em;
  }
  100% {
    -ms-flex-preferred-size: 10em;
        flex-basis: 10em;
  }
}