<script>.red { background: red; height: 100px; width: 100px; display: inline-flex; color: #fff; border-radius: 50%; justify-content: center; align-items: center; }</script>

Copy this code paste it in your website

<script>.red { background: red; height: 100px; width: 100px; display: inline-flex; color: #fff; border-radius: 50%; justify-content: center; align-items: center; }</script><div class="red">YOUR TEXT</div>