[{"createTime":1735734952000,"id":1,"img":"hwy_ms_500_252.jpeg","link":"https://activity.huaweicloud.com/cps.html?fromacct=261f35b6-af54-4511-a2ca-910fa15905d1&utm_source=V1g3MDY4NTY=&utm_medium=cps&utm_campaign=201905","name":"华为云秒杀","status":9,"txt":"华为云38元秒杀","type":1,"updateTime":1735747411000,"userId":3},{"createTime":1736173885000,"id":2,"img":"txy_480_300.png","link":"https://cloud.tencent.com/act/cps/redirect?redirect=1077&cps_key=edb15096bfff75effaaa8c8bb66138bd&from=console","name":"腾讯云秒杀","status":9,"txt":"腾讯云限量秒杀","type":1,"updateTime":1736173885000,"userId":3},{"createTime":1736177492000,"id":3,"img":"aly_251_140.png","link":"https://www.aliyun.com/minisite/goods?userCode=pwp8kmv3","memo":"","name":"阿里云","status":9,"txt":"阿里云2折起","type":1,"updateTime":1736177492000,"userId":3},{"createTime":1735660800000,"id":4,"img":"vultr_560_300.png","link":"https://www.vultr.com/?ref=9603742-8H","name":"Vultr","status":9,"txt":"Vultr送$100","type":1,"updateTime":1735660800000,"userId":3},{"createTime":1735660800000,"id":5,"img":"jdy_663_320.jpg","link":"https://3.cn/2ay1-e5t","name":"京东云","status":9,"txt":"京东云特惠专区","type":1,"updateTime":1735660800000,"userId":3},{"createTime":1735660800000,"id":6,"img":"new_ads.png","link":"https://www.iodraw.com/ads","name":"发布广告","status":9,"txt":"发布广告","type":1,"updateTime":1735660800000,"userId":3},{"createTime":1735660800000,"id":7,"img":"yun_910_50.png","link":"https://activity.huaweicloud.com/discount_area_v5/index.html?fromacct=261f35b6-af54-4511-a2ca-910fa15905d1&utm_source=aXhpYW95YW5nOA===&utm_medium=cps&utm_campaign=201905","name":"底部","status":9,"txt":"高性能云服务器2折起","type":2,"updateTime":1735660800000,"userId":3}]
<>简介
* 自定义属性，它包含的值可以在整个文档中重复使用。由自定义属性标记设定值，由var() 函数来获取值，
* 自定义属性受级联的约束，并从其父级继承其值。
<>基本用法
声明一个自定义属性，属性名需要以两个减号（–）开始，属性值则可以是任何有效的CSS值。和其他属性一样，自定义属性也是写在规则集之内的，如下：
el { --main-color: red; }
注意，规则集所指定的选择器定义了自定义属性的可见作用域。通常的最佳实践是定义在根伪类
:root下（看项目的根节点是什么，具体情况具体分析），这样就可以在HTML文档的任何地方访问到它了：
:root { --main-color: red; }
<>自定义属性的继承性
自定义属性会继承。这意味着如果在一个给定的元素上，没有为这个自定义属性设置值，在其父元素上的值会被使用。看这一段HTML：
<div class="one"> <div class="two"> <div class="three"></div> <div class="four"
></div> </div> </div> .two { --test: 10px; } .three { --test: 2em; }
在这个情况下， var(–test) 的结果分别是：
* 对于元素 class=“two” ：10px
* 对于元素 class=“three” ：2em
* 对于元素 class=“four” ：10px （继承自父属性）
* 对于元素 class=“one” ：非法值，会变成自定义属性的默认值
* val(),有两个参数，第一个参数是设置的值（变量），第二个参数的默认的值，定义的变量是区分大小写的
