三种CSS设置方法，任选其一
<template><div class="wrapper"></div></template><style>.wrapper {/*1.背景全屏固定,使用fixed定位，内容完全显示且可滚动查看*//* position: fixed;height: 100%;width: 100%;background: url("../assets/dd.png") no-repeat;background-size:100% 100%;overflow-y: scroll;overflow-x: hidden;*//*2.线性渐变色背景全屏缩放大小，不用定位,内容完全显示且可滚动查看*//*background: linear-gradient(to bottom right, blue, red) center center no-repeat;background-size: 100% 100%;overflow: hidden;min-height: 100vh;*//* 3.背景全屏缩放大小，内容完全显示且可滚动查看,绝对定位*/width: 100%;min-height: 100vh;background: url("../assets/bg.jpg") center center no-repeat;background-size: 100% 100%;position:absolute;}</style>
