<body>
<h1 style="color: red">css实现矩形边角加粗</h1>
<div class="main">
<span></span>
<span></span>
<span></span>
<span></span>
</div>
</body>
body{
display: flex;
justify-content: center;
flex-direction: column;
align-items: center;
}
.main{
position: relative;
width: 400px;
height: 200px;
border: 1px solid red;
}
.main span:nth-child(1){
position: absolute;
left: -5px;
top: -5px;
padding: 15px;
border-style: solid;
border-color: rebeccapurple;
border-width: 5px 0 0 5px;
}
.main span:nth-child(2){
position: absolute;
right: -5px;
top: -5px;
padding: 15px;
border-style: solid;
border-color: rebeccapurple;
border-width: 5px 5px 0 0;
}
.main span:nth-child(3){
position: absolute;
right: -5px;
bottom: -5px;
padding: 15px;
border-style: solid;
border-color: rebeccapurple;
border-width: 0 5px 5px 0;
}
.main span:nth-child(4){
position: absolute;
left: -5px;
bottom: -5px;
padding: 15px;
border-style: solid;
border-color: rebeccapurple;
border-width: 0 0 5px 5px;
}
