：：before的z-index

伪元素:before的z-index默认为auto，即没有指定特定的层叠顺序。伪元素的z-index会受到其所在元素的z-index的影响。在同一个层叠上下文中，层叠顺序从后向前依次是：背景和边框、负z-index、块级盒、浮动盒、行内盒、z-index:0、正z-index。因此，如果在:before伪元素上设置了z-index属性，它的层叠顺序会与其所在元素的其他元素相同。<span class="em">1</span><span class="em">2</span><span class="em">3</span>
#### 引用[.reference_title]
- *1* [CSS中灵活使用:before和:after](https://download.csdn.net/download/weixin_38656337/13621864)[target="_blank" data-report-click={"spm":"1018.2226.3001.9630","extra":{"utm_source":"vip_chatgpt_common_search_pc_result","utm_medium":"distribute.pc_search_result.none-task-cask-2~all~insert_cask~default-1-null.142^v93^chatsearchT3_2"}}] [.reference_item style="max-width: 50%"]
- *2* *3* [CSS 伪元素:before&:after 与z-index 的那点事](https://blog.csdn.net/weixin_39786141/article/details/119374123)[target="_blank" data-report-click={"spm":"1018.2226.3001.9630","extra":{"utm_source":"vip_chatgpt_common_search_pc_result","utm_medium":"distribute.pc_search_result.none-task-cask-2~all~insert_cask~default-1-null.142^v93^chatsearchT3_2"}}] [.reference_item style="max-width: 50%"]
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