css箭头效果

<div class="box">
    <p>向上箭头</p>       
    <div class="to_top"></div>       
    <p>向左箭头</p>        
    <div class="to_left"></div>        
    <p>向右箭头</p>        
    <div class="to_right"></div>        
    <p>向下箭头</p>        
    <div class="to_bottom"></div>    
</div>

CSS

.box {            
width: 400px;            
height: 100px;            
text-align: center;            
margin: 50px auto;        
}         
.box p {            
background: pink;       
 }        
 /* 向上箭头 */         
.to_top {            
width: 0;            
height: 0;            
border-bottom: 30px solid #f0f;            
border-left: 30px solid transparent;            
border-right: 30px solid transparent;        
}        
 /* 向左箭头 */         
.to_left {            
width: 0;            
height: 0;            
border-right: 30px solid #ffd900;            
border-top: 30px solid transparent;            
border-bottom: 30px solid transparent;        
}         
/* 向右箭头 */         
.to_right {            
width: 0;            
height: 0;            
border-left: 30px solid greenyellow;            
border-top: 30px solid transparent;            
border-bottom: 30px solid transparent;        
}         
/* 向下箭头 */         
.to_bottom {            
width: 0;            
height: 0;            
border-top: 30px solid skyblue;            
border-left: 30px solid transparent;            
border-right: 30px solid transparent;        
}