.top-nav{display:flex;背景：#fff；li{列表样式：无；弹性：1；文本对齐：居中；填充顶部：10px；a{文字装饰：无；显示：块；填充底部：8px；}。积极的{border-bottom:2pxsolid#ff0000;}}}在views文件下创建Layout.vue，Mine.vue、Search.vue、Topic.vue组件配置路由，Layout组件为入口文件，其他组件配置为Layout组件的子组件。点击高亮-->linkActiveClass:"active",上面代码constrouter=newVueRouter({mode:'history',base:process.env.BASE_URL,linkActiveClass:"active",//配置点击高亮路由：[{path:"/",name:"Layout",component:Layout,children:[{path:'/',name:'Home',component:Home},{path:'mine',name:'mine',component:Mine},{path:'search',name:'search',component:Search},{path:'topic',name:'topic',component:Topic}]}]})只有一个路由App.vue中留exit，删除App中的所有样式
