效果图
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
<style>
* {
box-sizing: border-box;
margin: 0;
padding: 0;
}
ul,
ol,
li {
list-style: none;
}
.flex {
display: flex;
}
.flex.-column {
flex-direction: column;
}
.flex.x-center {
justify-content: center;
}
.flex.y-center {
align-items: center;
}
.flex.xy-center {
justify-content: center;
align-items: center;
}
.h-full {
height: 100%;
}
.w-full {
width: 100%;
}
.full {
width: 100%;
height: 100%;
}
.title {
margin: 0 auto;
text-align: center;
}
header {
margin: 16px 0;
}
.page {