常用css

超出部分显示省略号

overflow: hidden;
text-overflow: ellipsis;
white-space: nowrap;

参考：https://blog.csdn.net/zhumengzj/article/details/80801556

三角形

#triangle-up {
    width: 0;
    height: 0;
    border-left: 50px solid transparent;
    border-right: 50px solid transparent;
    border-bottom: 100px solid red;
}

#triangle-topleft {
    width: 0;
    height: 0;
    border-top: 100px solid red;
    border-right: 100px solid transparent;
}