效果图：
完整代码：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
<meta name="viewport" content="width=device-width, initial-scale=1.0"/>
<title>【前端实例代码】使用html+css+JavaScript实现带有波浪跳跃动画的登录表单页面</title>
<style>
@import url("https://fonts.googleapis.com/css2?family=Muli&display=swap");
* {
box-sizing: border-box;
}
body {
background-color: #2D5CFE;
color: #fff;
font-family: "Multi", sans-serif;
display: flex;
flex-direction: column;