圆：
<code>.yuan{
width:100px;
height:100px;
-moz-border-radius:50%;
-webkit-border-radius:50%;
border-radius:50%;
background-color:red;
}
<div class="yuan"></div></code>
椭圆
<code>.oval {
width: 200px;
height: 100px;
background-color: red;
-moz-border-radius: 100px / 50px;
-webkit-border-radius: 100px / 50px;
border-radius: 100px / 50px;
}
<div class="oval"></div></code>
箭头：
<code>.arrow{
content: '';
position: absolute;
width: 30px;
height: 30px;
border: 10px solid #f5b24a;
-webkit-transform: rotate(-135deg);
-moz-transform: rotate(-135deg);
-o-transform: rotate(-135deg);
-ms-transform: rotate(-135deg);
transform: rotate(-135deg);
border-top: none;
border-right: none;
top: 9px;
}
<span class="arrow"></span></code>
三角形：
<code>.rencentle {
width: 0;
height: 0;
border-left: 50px solid transparent;
border-right: 50px solid transparent;
border-bottom: 100px solid red;
}
<div class="rencentle"></div></code>
