Here是一把小提琴.
<p>foo <a class="infolink" href="#">bar</a> baz</p>
和
a.infolink::before
{
content: '?';
background: blue;
color: white;
width: 20ex;
height: 20ex;
}
The '?' appears but clearly does not have 20ex size. Why not? Tested in Firefox 和 Chrome.