视觉差 

<section>
    最外面的图层
    <div class="section">带背景图片的层</div>
</section>

<style>
section {
  display: flex;
  justify-content: center;
  align-items: center;
}

.img1 {
  width: 100%;
  height: 640px;
  background-image: url(/src/pages/HomePage/imgs/npl-bg.png);
  background-size: 100% 100%;
  background-repeat: no-repeat;
  background-attachment: fixed;
  background-size: cover;
  background-position: center center;
}
</style>