为什么我设置margin-left -1边框还是重叠,第二个小li和第三个小li还是重合
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
ul li {
float: left;
list-style: none;
width: 100px;
height: 100px;
border: 1px solid red;
margin-left: -1px;
}
</style>
</head>
<body>
<ul>
<li></li>
<li></li>
<li></li>
<li></li>
</ul>
</body>
</html>