Die beiden < > um durch die offenen Tabs zu gehen, vegrößern, Farbe ändern ?

#scrollbutton-down > .toolbarbutton-icon {
    appearance: none !important;
    transform: scale(-1.5) !important;
}

#scrollbutton-up > .toolbarbutton-icon {
    transform: scale(1.5) !important;
}

[data-l10n-id="overflow-scroll-button-backwards"],
[data-l10n-id="overflow-scroll-button-forwards"] {
	appearance: none !important;
	background: green !important;
	fill: white !important;
	box-shadow: none !important;
	border: 2px solid red !important;
	height: 32px !important;
	overflow: hidden !important;
	margin-top: 7px !important;
	padding-top: 0 !important;
	padding-bottom: 0 !important;	
}