css图片宽度设置百分比，怎么让高度和宽度相等

<div style="display: flex;flex-wrap: wrap;">

　　<div class="box" v-for="item in 3" :key="item">
       <img src="https://img.yzcdn.cn/vant/cat.jpeg" />
　　</div>

</div>                     

.box{
        width: 32%;
        margin: 0.65%;
        padding-bottom: 32%;
        height: 0;
        position: relative;
        img{
               width: 100%;
               height: 100%;
               object-fit: cover;
               border-radius: 4px;
               position: absolute;
               top: 0;
               left: 0;
      }
                
}