Editing Template:Fraction/styles.css

/* {{pp|small=y}} */
.frac {
	white-space: nowrap;
}

.frac .num,
.frac .den {
	font-size: 80%;
	line-height: 0; /* we want this inline */
	vertical-align: super;
}

.frac .den {
	vertical-align: sub;
}

/* [[Template:Screen reader-only]] is canonical implementation onwiki */
.sr-only {
	border: 0;
	clip: rect(0, 0, 0, 0);
	height: 1px;
	margin: -1px;
	overflow: hidden;
	padding: 0;
	position: absolute;
	width: 1px;
	/* white-space: nowrap; /* already have nowrap above */
}