样式一

<!-- 来自BiliBili:https://www.bilibili.com/video/BV1tA411h7id/? -->
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>登录界面</title>
</head>
<body>
<div class="container">
<div class="login-wrapper">
<div class="header">Login</div>
<div class="form-wrapper">
<input type="text" name="username" placeholder="username" class="input-item">
<input type="password" name="password" placeholder="password" class="input-item">
<div class="btn">login</div>
</div>
<div class="msg">
Don`t have account? <a href="#">Sing up</a>
</div>
</div>
</div>
</body>
</html>
* {
margin: 0;
padding: 0;
/* 设置字体 */
font-family: "courier new";
/* 字母间距 */
letter-spacing: .05em;
}
html {
height: 100%;
}
body {
height: 100%;
}
.container {
height: 100%;
/* 背景色渐变效果 */
background-image: linear-gradient(to right, #fccb90 , #d57eeb);
}
.login-wrapper {
background-color: #fff;
width: 300px;
height: 500px;
/* 圆角 */
border-radius: 15px;
padding: 0 20px;
/* ----------居中---------- */
position: relative;
left: 50%;
top: 50%;
transform: translate(-50%, -50%);
/* ------------------------ */
}
.login-wrapper .header {
font-size: 30px;
font-weight: bold;
text-align: center;
line-height: 200px;
}
.form-wrapper .input-item {
display: block;
width: 100%;
margin-bottom: 20px;
border: 0;
padding: 10px;
border-bottom: 1px solid rgb(128, 125, 125);
font-size: 15px;
outline: none;
}
/* 部分浏览器不支持 */
.login-wrapper .form-wrapper .input-item :: placeholder{
/* 控制文本大小写 */
/* uppercase:全部大写 */
/* lowercase:全部小写 */
/* capitalize:首字母小写 */
/* text-transform: uppercase; */
}
.login-wrapper .form-wrapper .btn {
text-align: center;
padding: 10px;
margin-top: 40px;
border-radius: 15px;
background-image: linear-gradient(to right, #fccb90 , #d57eeb);
color: #fff;
cursor: pointer;
}
.login-wrapper .msg {
text-align: center;
line-height: 80px;
}
.login-wrapper .msg a {
text-decoration: none;
color: #d57eeb;
}
.login-wrapper .msg a:active {
color: #5C9900;
}
样式二