border-left-color:
border-top-width:中心距顶部距离
.userCard .welcome .triangle{ border: 8px solid transparent;width: 0px;height: 0px;border-left-color: #E8676B;border-top-width: 0;
}
结果 →
这篇博客很清楚,可借助参考:https://www.cnblogs.com/youhong/p/6530575.html