zotero/scss/components/_toolbarbutton.scss

toolbarbutton {
	appearance: none;
	flex-shrink: 0;
	&:not(.titlebar-button) {
		border-radius: 5px;
	}
	margin: 0;
	color: var(--fill-secondary);
	-moz-context-properties: fill, fill-opacity, stroke, stroke-opacity;
	background-color: transparent;


	.toolbarbutton-menu-dropmarker {
		-moz-default-appearance: none;
		display: block;
		visibility: visible;
		@include svgicon-menu("chevron-8", "universal", "8");
		color: var(--fill-secondary);
		width: 8px;
		height: 8px;
	}

	&:hover {
		background-color: var(--fill-quinary);
	}
	
	&:active, &[selected] {
		background-color: var(--fill-quarternary);
	}
	
	&:disabled,
	&[disabled="true"] {
		background-color: transparent;
		color: var(--fill-tertiary);

		.toolbarbutton-menu-dropmarker {
			color: var(--fill-tertiary);
		}
	}

	&[open="true"] {
		background-color: var(--fill-quarternary);
	}
}

@keyframes rotating {
	from {
		transform: rotate(0deg);
	}
	to {
		transform: rotate(360deg);
	}
}

toolbarbutton[status=animate] {
	.toolbarbutton-icon {
		color: var(--fill-secondary);
		animation: rotating 2s linear infinite;
	}
}

.zotero-tb-separator {
	height: 36px;
	border-right: var(--material-panedivider);
}

$toolbarbutton-icons: (
	collection-add: "add-collection",
	collections-search: "magnifier",
	add: "add-item",
	lookup: "magic-wand",
	attachment-add: "add-file",
	note-add: "note",
	tabs-menu: "chevron",
	sync-error: "error",
	sync: "sync",
);

@each $cls, $icon in $toolbarbutton-icons {
	#zotero-tb-#{$cls} {
		@include svgicon-menu($icon, "universal", "20");
	}
};