absolute定位层级不起作用

Question

<section class="page-7 page">
     <div class="music"></div>
     <div class="QR_code writ img-loading-list-none"></div>
     <div class="light writ img-loading-list-none"></div>
     <div class="fingerprint writ img-loading-list-none"></div>
</section>

.page-7 .fingerprint{ position: absolute; width: 1.575rem; height: 1.76rem; top: 2.97rem; left: 50%; margin-left:-0.7875rem; background-image: url("../img/fingerprint.png");background-size: 100%; z-index: 9999;}
.page-7 .light{ position: absolute; width: 0.905rem; height: 0.075rem; top: 3.57rem; left: 1.17rem; background-image: url("../img/light.png");background-size: 100%;  z-index: 999;}

section 设置的相对定位，light是那条线，fingerprint是手印，按说fingerprint层在html结构中在下面就应该覆盖住light，但是不行，我设置了z-index还是不起作用

Answer 1

你这俩png带透明度么？