lovecoding
/
W260426


			
				
					
						
						
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							<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box{
            border: 3px solid black;
            /* height: 200px; */
        }
        .item{
            width: 200px;
            height: 200px;
            background-color: red;
            float: left;
        }
        .box2{
            height: 300px;
            width: 300px;
            background-color: blue;
        }
        /* p{
            clear: both;
        } */
         /* ::after 伪元素 */
         /* 在当前元素中最后面添加一个伪元素（假的标签） */
        .box::after{
            /* content 伪元素的内容 必须要有  伪元素默认为行元素*/
            content: "";
            /* display 块级元素 */
            display: block;
            /* clear 清除浮动. 必须作用于块级元素上 */
            clear: both;
        } 
    </style>
</head>
<body>
    <div class="box">
        <div class="item">1</div>
        <div class="item">2</div>
        <div class="item">3</div>
        <!-- <p></p> -->
    </div>
    <div class="box2"></div>
</body>
</html>