button-group vertical -> displayed as horizontal

[Jorge]

Hi

Congratulations for this nice project !

For sure not a big issue, but:
button-group vertical
-> are displayed horizontal

(tested in Chrome & Firefox)

<button-group name="type" vertical>
	<button value="garlic" aria-pressed="true">Garlic</button>
	<button value="msg">MSG</button>
	<button value="salt">Salt</button>
</button-group>

[Lea Verou]

Looks like a recent change broke it, I just fixed it, thanks!