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<p><strong>scale(1)</strong>: обычный размер</p>
<p><strong>scale(2)</strong>: двойной размер</p>
<p><strong>scale(0.5)</strong>: половина размера</p>
<p><strong>scale(0)</strong>: нулевой размер (невидим)</p>
<p><strong>scale(-1)</strong>: отражение</p>
<div>Масштаб</div>

p {
  animation: scaling-toggle 10s steps(1) 0s infinite forwards;
  background: white;
  color: grey;
  left: 2rem;
  margin: 0;
  opacity: 0;
  padding: 0 0.5em;
  position: absolute;
  top: 2rem;
  z-index: 1;
}

p:first-child {
  left: 0;
  position: relative;
  top: 0;
}

p:nth-child(2) {
  animation-delay: 2s;
}

p:nth-child(3) {
  animation-delay: 4s;
}

p:nth-child(4) {
  animation-delay: 6s;
}

p:nth-child(5) {
  animation-delay: 8s;
}

p strong {
  content: "";
  display: inline-block;
}

div {
  animation: scaling 10s linear 0s infinite;
  background: goldenrod;
  border-radius: 60px;
  color: white;
  height: 120px;
  line-height: 120px;
  margin-top: 2rem;
  ;
  text-align: center;
  transition: all 100ms linear;
  width: 120px;
}

@keyframes scaling {
  0% {
    transform: scale(1);
  }
  19% {
    transform: scale(1);
  }
  20% {
    transform: scale(2);
  }
  39% {
    transform: scale(2);
  }
  40% {
    transform: scale(0.5);
  }
  59% {
    transform: scale(0.5);
  }
  60% {
    transform: scale(0);
  }
  79% {
    transform: scale(0);
  }
  80% {
    transform: scale(-1);
  }
  99% {
    transform: scale(-1);
  }
  100% {
    transform: scale(1);
  }
}

@keyframes scaling-toggle {
  0% {
    opacity: 1;
  }
  20% {
    opacity: 0;
  }
  100% {
    opacity: 0;
  }
}