关键代码
background-image: url("../../assets/images/navbar-banner.png");//图片地址background-repeat: no-repeat;//不重复background-position-x: center;//居中background-position-y: center;//居中background-size: contain;//不会改变图片的宽高比background-size: 100% 100%;//改变图片适应容器宽高比background-size: 100px 100px;//改变图片适应容器宽高值
