JSFiddle - React, Tailwind, and code Playground
by Manuel Souto Pico
HTML
before <span class="math-box"><span class="vstack"><div style="top: 0.686em;">8</div><div style="top: -0.23em;"><span class="frac-line"></span></div><div style="top: -0.677em;">1234</div><span class="baseline-fix"></span></span></span> after
CSS
.math-box {
display: inline-block;
}
.math-box .vstack {
display: inline-block;
position: relative;
}
.math-box .vstack > div {
position: relative;
text-align: center;
height: 0;
}
.math-box .baseline-fix {
display: inline-table;
table-layout: fixed;
}
.math-box .frac-line {
width: 100%;
display: inline-block;
}
.math-box .frac-line:before {
display: block;
border-bottom-style: solid;
border-bottom-width: 1px;
content: "";
}
.math-box .frac-line:after {
display: block;
margin-top: -1px;
border-bottom-style: solid;
border-bottom-width: 0.04em;
content: "";
}