弹性盒模型的样式布局
.nav_list{
flex:1;
flex-wrap:wrap;
display:flex;
flex-direction:row;
justify-content:space-between;
}
.hot-item{
width:312rpx;
height:316rpx;
background:#fff;
margin-bottom:30rpx;
box-shadow: -0rpx 6rpx 10rpx 4rpx #dedcdc;
}