::before with input in Firefox

Question

I'm trying to put some content before an input tag using CSS pseudo-class ::before. It works in Chrome but not in Firefox. What seems to be the problem with Firefox?

Here's a snippet:

input::before {
	content: '';
	display: block;
	width: 13px;
	height: 13px;
	border-radius: 50%;
	box-shadow: 0px 0px 5px #9F0002 inset;
}

<input type="radio" name="gender" class="radio" value="male">male
<input type="radio" name="gender" class="radio" value="female">female

...and here's the outcome. Chrome works just fine:

but there are no changes in Firefox:

Solution

According to the specification.

Authors specify the style and location of generated content with the :before and :after pseudo-elements. As their names indicate, the :before and :after pseudo-elements specify the location of content before and after an element's document tree content. The 'content' property, in conjunction with these pseudo-elements, specifies what is inserted.

:before and :after should only work on the element which can act as a container of content. <input> cannot contain any content so it should not support those pseudo-elements. Chrome supports because it does not follow the spec (or bug?).