JSFiddle - React, Tailwind, and code Playground

by Liane Stevenson

HTML

<div class="circle-outer">
  <a href="https://www.w3schools.com"><button class="circle">Click me</button></a>
</div>

CSS

body, html {
  height: 100%;
  display: grid;
}

.circle-outer {
  margin: auto;
  text-align: center;
}

button.circle {
  --startSize: 65vh;
  --endSize: 85vh;
  width: var(--startSize);
  height: var(--startSize);
  background: teal;
  border-radius: 100%;
  animation-name: breathe;
  animation-play-state: running;
  animation-duration: 4.5s;
  animation-iteration-count: infinite;
  animation-direction: alternate;
    border: none;

}

@keyframes breathe {
  
  0% {
    width: var(--startSize); 
    height: var(--startSize);
  }
  
  25% {
    width: var(--startSize); 
    height: var(--startSize);
  }

  75% {
    width: var(--endSize);
    height: var(--endSize);
  }
  
  100% {
    width: var(--endSize);
    height: var(--endSize);
  }
}