方式一
<style>
.border {
width: 200px;
height: 200px;
position: relative;
}
.border::before {
content: "";
position: absolute;
left:0;
top: 0;
width: 200%;
height: 200%;
border: 1px solid blue;
transform-origin: 0 0;
transform: scale(0.5);
}
</style>
<div class="border"></div>
方式二
<style>
.border {
width: 200px;
height: 200px;
position: relative;
}
.border::before {
position: absolute;
box-sizing: border-box;
content: " ";
pointer-events: none;
top: -50%;
right: -50%;
bottom: -50%;
left: -50%;
border: 1px solid blue;
transform: scale(0.5);
}
</style>
<div class="border"></div>
作者：很晚很晚了
来源：juejin.cn/post/7255147749360156730
