老师，检查下代码为什么图却不变

来源：1-2 编程练习

流下了没有技术的眼泪

2020-03-16 17:36:06

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style>
    *{
        padding: 0;
        margin: 0;
    }
        .blue{
            width: 100px;
            height: 100px;
            background: blue;
            /*在此处添加相应代码*/
            position: relative;
            top: 50px;
            left: 50px;
            
            
        }
        .red{
            width: 100px;
            height: 100px;
            background: red;   

        }
    </style>
</head>
<body>
    <div class="blue"></div>
    <div class="red"></div>
</body>
</html>