build_html/delivery/static/css/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;
  }
}

/* 自定义顶部导航栏 start */
.custom-navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 9999;

  /* 返回按钮 */
  &__back {
    position: absolute;
    left: 30rpx;
    display: flex;
    align-items: center;
    justify-content: center;
    // padding: 0px 30rpx;
    // border-radius: 30rpx;
    font-size: 40rpx;
  }
  
  /* 标题 */
  &__title {
    position: absolute;
    left: 50%;
    line-height: 1;
    transform: translateX(-50%) translateY(50%);
    font-size: 32rpx;
  }
}
/* 自定义顶部导航栏 end */