JSFiddle - React, Tailwind, and code Playground

HTML

<!--框外边顶部向上三角的css写法-->
<div class="arrow_box">
    content<br />
</div>
<br /><br />
<div class="left_arrow_box">
    content<br />
    content<br />
    content<br />
    content<br />
    content<br />
    content<br />
    content<br />
    content<br />
</div>

CSS

/*-------------------------------------*/
/* 顶部三角的样式*/
/*-------------------------------------*/
.arrow_box {
    background: #FEFEFE;
    filter: progid:DXImageTransform.Microsoft.Gradient(gradientType=0,startColorStr=#FEFEFE,endColorStr=#F0F0F0);
    -ms-filter: "progid:DXImageTransform.Microsoft.Gradient(gradientType=0,startColorStr=#FEFEFE,endColorStr=#F0F0F0)";
    background: -webkit-gradient(linear, left top, left bottom, from(#FEFEFE), to(#F0F0F0));
    background: -moz-linear-gradient(center top , #FEFEFE 0%, #F0F0F0 100%) repeat scroll 0 0 transparent;
    border: 4px solid #EDEDED;
    position: relative;
    -webkit-border-radius: 5px;
    -moz-border-radius: 5px;
    border-radius: 5px;
    -webkit-box-shadow: 0 0 0 1px #F8F8F8;
    -moz-box-shadow: 0 0 0 1px #F8F8F8;
    box-shadow: 0 0 0 1px #F8F8F8;
    padding: 10px;
    margin: 20px 0px;
}
.arrow_box:after, .arrow_box:before {
    border: medium solid transparent;
    bottom: 100%;
    content: " ";
    height: 0;
    pointer-events: none;
    position: absolute;
    width: 0;
}
.arrow_box:after {
    border-bottom-color: #F4F4F4;
    border-width: 10px;
    left: 28px;
    margin-left: -10px;
}
.arrow_box:before {
    border-bottom-color: #EEEEEE;
    border-width: 18px;
    left: 28px;
    margin-left: -18px;
}

/*-------------------------------------*/
/* 左侧三角的样式*/
/*-------------------------------------*/
.left_arrow_box {
    background: none repeat scroll 0 0 #FFF;
    border: 6px solid rgba(190,190,190,0.3);
    position: relative;
	-webkit-border-radius: 5px;
	   -moz-border-radius: 5px;
	        border-radius: 5px;
	-webkit-box-shadow: 0 0 0 1px #FFFFFF inset, 0 0 0 2px #F4F4F4 inset;
	    -moz-box-shadow: 0 0 0 1px #FFFFFF inset, 0 0 0 2px #F4F4F4 inset;
	        box-shadow: 0 0 0 1px #FFFFFF inset, 0 0 0 2px #F4F4F4 inset;

}
.left_arrow_box:after, .left_arrow_box:before {
	right: 100%;
	border: medium solid transparent;
	content: " ";
	height: 0;
	width: 0;
	position:...