/* ========== 回到顶部按钮（全站共用） ========== */
#backToTop {
	position: fixed;
	right: 28px;
	bottom: 32px;
	width: 46px;
	height: 46px;
	border: none;
	border-radius: 50%;
	background: #4a6cf7;
	color: #fff;
	display: flex;
	align-items: center;
	justify-content: center;
	cursor: pointer;
	box-shadow: 0 6px 18px rgba(74, 108, 247, 0.4);
	opacity: 0;
	visibility: hidden;
	transform: translateY(12px);
	transition: opacity .25s ease, transform .25s ease, visibility .25s, background .2s;
	z-index: 1040;
}
#backToTop.show {
	opacity: 1;
	visibility: visible;
	transform: translateY(0);
}
#backToTop:hover {
	background: #3b5bdb;
}
#backToTop:active {
	transform: translateY(0) scale(0.94);
}
#backToTop svg {
	display: block;
}
/* 深色主题适配 */
[data-bs-theme="dark"] #backToTop {
	background: #5c7cfa;
	box-shadow: 0 6px 18px rgba(92, 124, 250, 0.45);
}
[data-bs-theme="dark"] #backToTop:hover {
	background: #748ffc;
}