JSFiddle - React, Tailwind, and code Playground

HTML

<div class="kreis">
  <p></p>
</div>

CSS

.kreis {
    display:block;
    width:60px;
    height:60px;
    line-height:80px;
    border: 2px solid #f5f5f5;
    border-radius: 60px;
    color:black;
    background: yellow;
    box-shadow: 0 0 3px gray;
    font-size:20px;
    font-weight:bold;
    position: absolute;
    -webkit-border-radius: 60px;
    -moz-border-radius: 60px;
    border-radius: 60px;
     -webkit-animation-name: pulsate;
     -webkit-animation-duration: 2s;
    -webkit-animation-timing-function: ease-in-out;
    -webkit-animation-iteration-count: infinite;
    -webkit-animation-delay: 1s;
     -moz-animation-name: pulsate;
     -moz-animation-duration: 2s;
    -moz-animation-timing-function: ease-in-out;
    -moz-animation-iteration-count: infinite;
    -moz-animation-delay: 1s;
     animation-name: pulsate;
     animation-duration: 2s;
       animation-timing-function: ease-in-out;
    animation-iteration-count: infinite;
    animation-delay: 1s;
}
p {
    margin-bottom: auto;
    margin-top: auto;
    text-align: center;
}
 
@-webkit-keyframes 'pulsate' {
    0% {
        -webkit-transform: scale(0.9,0.9);
        -moz-transform: scale(0.9,0.9);
        -ms-transform: scale(0.9,0.9);
        transform: scale(0.9,0.9);
        opacity: 0.0
    }
    12% {
        opacity: .5
    }
    25% {
        -webkit-transform: scale(1.2, 1.2);
        -moz-transform: scale(1.2, 1.2);
        -ms-transform: scale(1.2, 1.2);
        transform: scale(1.2, 1.2);
        opacity: 0.0
    }
}