箭头方向

<style>
.a1{ display:inline-block; border-color: transparent; border-style: solid; border-left-color: #c63d35; border-width: 5px 0 5px 5px;}
.a2{ display:inline-block; border-color: transparent; border-style: solid; border-right-color: #c63d35; border-width: 5px 5px 5px 0 ;}
.a3{ display:inline-block; border-color: transparent; border-style: solid; border-top-color: #c63d35 ;border-width: 5px 5px 0 5px;}
.a4{ display:inline-block; border-color: transparent; border-style: solid; border-bottom-color: #c63d35 ;border-width: 0 5px 5px 5px;}
</style>
<div class="a1"></div>
<div class="a2"></div>
<div class="a3"></div>
<div class="a4"></div>

箭头方向

原文：http://www.cnblogs.com/mrt-yyy/p/5332419.html