整个项目使用文件：
HTML代码部分：
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>登录注册页面</title><!-- 引入 CSS --><link rel="stylesheet" href="./CSS/login.css"><script src="./JS/login.js"></script>
</head>
<body><div class=".bigbox"><form action="" class="login"><h1>login</h1><img src="./img/user.png" alt=""><input type="text" placeholder="用户名" required><img src="./img/passwd.png" alt=""><input type="text" placeholder="密码" required><input type="submit" class="btn" value="登录"></form></div>
</body>
</html>CSS代码部分：
* {user-select: none; /*无法选中，整体感更强*/
}body {/*设置背景*/background-image: url(../img/backgroud.jpg);/*平铺*/background-repeat: no-repeat;/*按照屏幕大小计算尺寸*/background-size: cover;background-attachment: fixed;
}.login {/*绝对定位*/position:absolute;/*设置位置，距离顶部50%，外边框-200px，距离左边50%*/top: 50%;margin-top: -200px;left: 50%;/*form表单宽度为400px，这里回200px*/margin-left: -200px;width: 400px;height: 400px;/*边框锐度*/border-radius: 25px;background-color: aquamarine;/*居中*/text-align: center;padding: 5px 40px;/*盒子*/box-sizing: border-box;/*阴影*/box-shadow: 5px 10px 5px #161616;
}.login h1 {font-family: "微软雅黑";color: blueviolet;
}input{/*设置背景颜色*/background-color: cornflowerblue;height: 48px;width: 80%;/*设置据底部距离*/margin-bottom: 10px;border: 0px;border-bottom: 2px solid silver;/*点击白色去除*/outline: none;/*更改字体大小和颜色变化*/font-size: 22px;color: white;
}form img {width: 32px;top: 5px;position: relative;
}.btn {width: 40%;background-image: linear-gradient(120deg,pink 0%,red 100%);border-radius: 25px;
}.btn:hover{background-image: linear-gradient(to right,green 0%,blueviolet 100%);
}页面效果图如下：
