通过js设置样式

   

    
    if(document.getElementById("B").style.display == 'none'){
      document.getElementById("B").style.display = "flex"
      document.getElementById("B").style['align-items'] ="center"
      document.getElementById("B").style['justify-content'] ="center"
    }else{
      document.getElementById("B").style.display = "none"
    }
    $('.banner-nav li').eq(i).addClass('hover').siblings('li').removeClass('hover');