examtest_mp/pages/material/video.wxss

.head{
  color:#fff;
  background-color: cornflowerblue;
  text-align: center;
}
.txv-video-slot{
  width: 100%;
  height: 40px;
  line-height: 40px;
  font-size: 16px;
  color:white;
  background-color: black;
  opacity:0.3;
}