JSFiddle - React, Tailwind, and code Playground

HTML

<section></section>

CSS

section {
            width: 300px;
            height: 300px;
            background-color: lightblue;

            -webkit-animation: blink step-start 1s 0s infinite;
            animation: blink step-start 1s 0s infinite;
        }

        @-webkit-keyframes blink {
            0% { box-shadow: red 0 0 50px; }
            50% { box-shadow: white 0 0 50px; }
            100% { box-shadow: red 0 0 50px; }
        }

        @keyframes blink {
            0% { box-shadow: red 0 0 50px; }
            50% { box-shadow: white 0 0 50px; }
            100% { box-shadow: red 0 0 50px; }
        }