JSFiddle - React, Tailwind, and code Playground

HTML

<span>a</span>
<span>ab</span>
<span>abc</span>
<span>abcd</span>
<span>abcd<br />a</span>
<span>abcd<br />abcd<br />abcd<br />abcd</span>
<span>abcdefghijkl<br />abcdef</span>

CSS

span {
    display: inline-block;
    padding: 15px;
    line-height: 100%;

    -moz-border-radius: 50%;
    border-radius: 50%;

    background-color: black;
    color: white;
    text-align: center;
    font-size: 2em;
}