add shadow to tabBar of uni-app

I added the following css code in app.vue

There is no problem on the h5 end, there are shadows, but not on the app end, ask how to add shadows on the app end

 uni-tabbar, uni-tabbar .uni-tabbar{
    
      
        box-shadow: 0px -2px 10px 0px rgba(132,85,250,0.82);  
    }