我们一般在打开相机的时候有个扫描框，然后静态二维码有时候为了聚焦和利于扫描也会加一个框框，下面介绍一下如何通过css 来实现一个框框
实现效果:

代码如下:

html:

<div class="img-box">
    <img class="code"  src="https://image-static.segmentfault.com/149/570/149570997-5b987cc928d69_articlex">
</div>

css:

.img-box {
  background: linear-gradient(#ae0000, #ae0000) left top,
    linear-gradient(#ae0000, #ae0000) left top,
    linear-gradient(#ae0000, #ae0000) right top,
    linear-gradient(#ae0000, #ae0000) right top,
    linear-gradient(#ae0000, #ae0000) right bottom,
    linear-gradient(#ae0000, #ae0000) right bottom,
    linear-gradient(#ae0000, #ae0000) left bottom,
    linear-gradient(#ae0000, #ae0000) left bottom;
  background-repeat: no-repeat;
  background-size: 2px 20px, 20px 2px;
  height: 116px;
  width: 116px;
}        
.code {
    height: 110px;
    width: 110px;
    margin-top: 2px;
    margin-left:2px;
    border: 1px solid #ae0000;
}