#sttb-button {
	position: fixed;
	bottom: 20px;
	z-index: 99999;
	width: var(--sttb-size, 48px);
	height: var(--sttb-size, 48px);
	padding: 0;
	margin: 0;
	border: 0;
	border-radius: 50%;
	background: var(--sttb-bg, #111);
	color: var(--sttb-fg, #fff);
	display: flex;
	align-items: center;
	justify-content: center;
	cursor: pointer;
	box-shadow: 0 4px 14px rgba(0, 0, 0, .25);
	opacity: 0;
	visibility: hidden;
	transform: translateY(12px);
	transition: opacity .25s ease, transform .25s ease, visibility .25s;
	-webkit-tap-highlight-color: transparent;
}
#sttb-button.sttb-visible {
	opacity: .9;
	visibility: visible;
	transform: translateY(0);
}
#sttb-button:hover { opacity: 1; transform: translateY(-2px); }
#sttb-button:focus-visible { outline: 3px solid var(--sttb-fg, #fff); outline-offset: 3px; }
#sttb-button svg { display: block; pointer-events: none; }
@media (max-width: 600px) {
	#sttb-button { bottom: 16px; }
}
@media (prefers-reduced-motion: reduce) {
	#sttb-button { transition: none; }
}