JSFiddle - React, Tailwind, and code Playground

HTML

<div class="critical">oh noes!</div>

CSS

.critical {
    -moz-animation: warning 2s infinite;
    -webkit-animation: warning 2s infinite;
    -o-animation: warning 2s infinite;
    -ms-animation: warning 2s infinite;
    animation: warning 2s infinite;
    color: white;
}


/* animation keyframes */
@-moz-keyframes warning {
    0% { background-color: rgb(244, 0, 63); }
    50% { background-color: rgb(241, 131, 8); }
    100% { background-color: rgb(244, 0, 63); }
}
@-ms-keyframes warning {
    0% { background-color: rgb(244, 0, 63); }
    50% { background-color: rgb(241, 131, 8); }
    100% { background-color: rgb(244, 0, 63); }
}
@-o-keyframes warning {
    0% { background-color: rgb(244, 0, 63); }
    50% { background-color: rgb(241, 131, 8); }
    100% { background-color: rgb(244, 0, 63); }
}
@-webkit-keyframes warning {
    0% { background-color: rgb(244, 0, 63); }
    50% { background-color: rgb(241, 131, 8); }
    100% { background-color: rgb(244, 0, 63); }
}
@keyframes warning {
    0% { background-color: rgb(244, 0, 63); }
    50% { background-color: rgb(241, 131, 8); }
    100% { background-color: rgb(244, 0, 63); }
}