/* ============================================================================
   wt_expand.css - 标题/目录展开收起按钮（wh_expand_btn）样式
   模块：展开态箭头旋转 / 默认箭头图标与悬停 / 移动端 768px 适配
   ============================================================================ */
/* Expand / collapse */
/* 2026-10-13 更新点：PC 端箭头改用左侧目录导航同款图标（收起/展开各一张图，不靠旋转切换）。 */
.wh_expand_btn.expanded:before {
    content:"";
	background-image: url("../images/leftnav-expand@2x.png");
	transform: none;
}
.wh_expand_btn.expanded:before:hover {
    content:"";
	transform: none;
}

/* 默认箭头图标，悬停仅提亮 */
/* 2026-10-13 更新点：收起态用左侧目录导航收起图标，展开态换用展开图标（见上）。 */
.wh_expand_btn:before {
    content:"";
    display: inline-block;
	/* 2026-10-13 更新点：图标由 16px 稍微放大到 18px。 */
	width: 18px;
	height: 18px;
	background-image: url("../images/leftnav-collapse@2x.png");
	background-size: 18px 18px;
    margin-right: 12px;
    /* 2026-10-13 更新点：目录导航图标颜色较浅，取消半透明，保持原图标色。 */
    opacity: 1;
	/* 2026-08-22 更新点：箭头与正文展开收起统一为250ms过渡。 */
	transition: none;
}
.wh_expand_btn:before:hover {
    content:"";
    opacity: 1;
}
.wh_expand_btn {
    cursor: pointer;
}

/* ==== 移动端 768px 以下适配：换用移动端小尺寸箭头图标 ==== */
@media only screen and (max-width: 768px) {
	.wh_expand_btn.expanded:before {
		content:"";
		/* display: inline-block;
		width: 12px;
		height: 12px;
		background-image: url("../images_m/title-collapse-down.png"); */
		transform: rotate(90deg);
		/* background-size: 12px 12px;
		margin-right: 12px;
		position: relative;
		top: 2.5px; 向下移动 */
	}
	.wh_expand_btn:before {
		content:"";
		display: inline-block;
		width: 12px;
		height: 12px;
		background-image: url("../images_m/collapse.png");
		background-size: 12px 12px;
		margin-right: 12px;
		position: relative;
		top: 2.5px;
		transition: transform 0.25s ease;
	}


	/* .wh_expand_btn.expanded:before:hover {
		content:"";
		/* display: inline-block;
		width: 12px;
		height: 12px;
		background-image: url("../images/title-collapse-down.png"); */
		/* transform: rotate(180deg); */
		/* background-size: 12px 12px;
		margin-right: 12px;
		position: relative;
		top: 2.5px;
	} */

	/* .wh_expand_btn:before:hover {
		content:"";
		display: inline-block;
		width: 12px;
		height: 12px;
		background-image: url("../images/title-collapse-down.png");
		background-size: 12px 12px;
		margin-right: 12px;
		position: relative;
		top: 2.5px;
	}  */

}