kaoshi/addons/exam/uniapp/static/css/templatePage/custom_nav_bar.scss

.tn-custom-nav-bar__back {
  width: 100%;
  height: 100%;
  position: relative;
  display: flex;
  justify-content: space-evenly;
  align-items: center;
  box-sizing: border-box;
  background-color: rgba(0, 0, 0, 0.15);
  border-radius: 1000rpx;
  border: 1rpx solid rgba(255, 255, 255, 0.5);
  color: #FFFFFF;
  font-size: 18px;
  
  .icon {
    display: block;
    flex: 1;
    margin: auto;
    text-align: center;
  }
  
  &:before {
    content: " ";
    width: 1rpx;
    height: 110%;
    position: absolute;
    top: 22.5%;
    left: 0;
    right: 0;
    margin: auto;
    transform: scale(0.5);
    transform-origin: 0 0;
    pointer-events: none;
    box-sizing: border-box;
    opacity: 0.7;
    background-color: #FFFFFF;
  }
}