How to make pinned tabs in Firefox a bit wider

I'm using Stylish to apply this, but I guess you could do it with a userChrome.css.

	@namespace url(http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul);
	.tabbrowser-tab[pinned] {
	width: 72px;
	}

view raw styles.css hosted with ❤ by GitHub

The main reason I want this is so the hit target is larger. I want to be able to click my pinned app tabs (currently a TiddlyWiki and my Zimbra corporate calendar) without aiming too hard.