#zotero-feed-item-addTo-button {
	margin: 5px 6px 3px;
	padding-left: 8px;
}

#zotero-feed-item-addTo-button button {
	margin: 0;
	-moz-appearance: none;
}
Fix feed item add-to button appearance on OS X
Fix feed item add-to button appearance on OS X
