Document
*{
margin: 0;
padding: 0;
}
/*transparent 为透明*/
/*箭头向下*/
.box-down{
display: inline-block;
width: 0;
height: 0;
border-right: 30px solid transparent;
border-left: 30px solid transparent;
border-bottom: 50px solid red;
}
/*箭头向上*/
.box-up{
display: inline-block;
width: 0;
height: 0;
border-left:30px solid transparent;
border-right: 30px solid transparent;
border-top:50px solid green;
}
/*箭头向左*/
.box-left{
display: inline-block;
width: 0;
height: 0;
border-top: 30px solid transparent;
border-left: 50px solid pink;
border-bottom: 30px solid transparent;
margin-left: 20px;
}
/*箭头向右*/
.box-right{
display: inline-block;
width: 0;
height: 0;
border-top: 30px solid transparent;
border-right: 50px solid orange;
border-bottom: 30px solid transparent;
}
