#a1-stl-overlay {
	display: none;
	position: fixed;
	inset: 0;
	background: rgba(0, 0, 0, 0.75);
	z-index: 999999;
	align-items: center;
	justify-content: center;
}
#a1-stl-overlay.a1-stl-visible {
	display: flex;
}

#a1-stl-modal {
	position: relative;
	width: 80vw;
	height: 80vh;
	max-width: 900px;
	max-height: 700px;
	background: #1a1a1a;
	border-radius: 4px;
	overflow: hidden;
}

#a1-stl-canvas {
	display: none;
	width: 100%;
	height: 100%;
}

#a1-stl-close {
	position: absolute;
	top: 10px;
	right: 12px;
	z-index: 10;
	background: rgba(0, 0, 0, 0.5);
	color: #fff;
	border: none;
	border-radius: 50%;
	width: 32px;
	height: 32px;
	font-size: 16px;
	line-height: 1;
	cursor: pointer;
}
#a1-stl-close:hover {
	background: rgba(255, 255, 255, 0.2);
}

#a1-stl-spinner {
	position: absolute;
	inset: 0;
	display: flex;
	align-items: center;
	justify-content: center;
	color: #aaa;
	font-size: 14px;
	pointer-events: none;
}
#a1-stl-spinner.a1-stl-spinning::before {
	content: '';
	display: block;
	width: 40px;
	height: 40px;
	border: 4px solid rgba(255, 255, 255, 0.15);
	border-top-color: #7ecfff;
	border-radius: 50%;
	animation: a1-spin 0.8s linear infinite;
}
@keyframes a1-spin {
	to { transform: rotate(360deg); }
}

/* ── Interaction hint ───────────────────────────────────────────────────────── */
.a1-stl-hint {
	position: absolute;
	bottom: 28px;
	left: 50%;
	transform: translateX(-50%) translateY(8px);
	display: flex;
	gap: 36px;
	background: rgba(0, 0, 0, 0.6);
	border-radius: 10px;
	padding: 14px 28px;
	pointer-events: none;
	z-index: 5;
	animation: a1-hint-life 4s ease forwards;
}

@keyframes a1-hint-life {
	0%   { opacity: 0; transform: translateX(-50%) translateY(8px); }
	12%  { opacity: 1; transform: translateX(-50%) translateY(0); }
	72%  { opacity: 1; transform: translateX(-50%) translateY(0); }
	100% { opacity: 0; transform: translateX(-50%) translateY(0); }
}

.a1-hint-item {
	display: flex;
	flex-direction: column;
	align-items: center;
	gap: 10px;
	color: rgba(255, 255, 255, 0.85);
	font-size: 11px;
	font-family: system-ui, sans-serif;
	letter-spacing: 0.6px;
	text-transform: uppercase;
	white-space: nowrap;
}

/* ── CSS mouse shape ── */
.a1-hint-mouse {
	width: 20px;
	height: 30px;
	border: 2px solid rgba(255, 255, 255, 0.8);
	border-radius: 10px;
	position: relative;
	flex-shrink: 0;
}

/* scroll wheel line */
.a1-hint-mouse::after {
	content: '';
	position: absolute;
	top: 5px;
	left: 50%;
	width: 2px;
	height: 6px;
	background: rgba(255, 255, 255, 0.8);
	border-radius: 1px;
	transform: translateX(-50%);
}

/* left mouse button divider */
.a1-hint-mouse::before {
	content: '';
	position: absolute;
	top: 0;
	left: 50%;
	width: 1px;
	height: 11px;
	background: rgba(255, 255, 255, 0.4);
}

/* ── Drag hint ── */
.a1-hint-drag-row {
	display: flex;
	align-items: center;
	gap: 8px;
}

.a1-hint-drag-row .a1-hint-mouse {
	animation: a1-drag-move 1.5s ease-in-out infinite;
}

@keyframes a1-drag-move {
	0%   { transform: translateX(-8px); }
	50%  { transform: translateX(8px); }
	100% { transform: translateX(-8px); }
}

.a1-hint-arrow {
	color: rgba(255, 255, 255, 0.6);
	font-size: 16px;
	line-height: 1;
}

/* ── Scroll hint ── */
.a1-hint-scroll-mouse::after {
	animation: a1-scroll-move 1.2s ease-in-out infinite;
}

@keyframes a1-scroll-move {
	0%   { transform: translateX(-50%) translateY(0);  opacity: 1; }
	55%  { transform: translateX(-50%) translateY(7px); opacity: 0; }
	56%  { transform: translateX(-50%) translateY(0);  opacity: 0; }
	100% { transform: translateX(-50%) translateY(0);  opacity: 1; }
}