epp/weixin-miniprogram/app.wxss

/**app.wxss**/
/* 右上角小红点 */
.add-dot {
  position: relative;
}

.add-dot::after {
  content: " ";
  position: absolute;
  right: -8rpx;
  top: -3rpx;
  width: 12rpx;
  height: 12rpx;
  background-color: red;
  border-radius: 50%;
}