尖角.css

.info-bubble span{
  width: 0;
  height: 0;
  font-size: 0;
  overflow: hidden;
  position: absolute;
}
/**/
.info-bubble span.tail{
  border-width: 16px;
  border-style: solid dashed dashed;
  border-color: rgba(150,150,150,0.2) transparent transparent;
  left: 20px;
  bottom: -34px;
}
.info-bubble span.top{
  border-width: 16px;
  border-style: solid dashed dashed;
  border-color: #ffffff transparent transparent;
  left: 20px;
  bottom: -32px;
}