css制作的圆，三角形，椭圆，箭头图标

圆：

.yuan{
  width:100px;
  height:100px;
  -moz-border-radius:50%;
  -webkit-border-radius:50%;
  border-radius:50%;
  background-color:red;
}
<div class="yuan"></div>

椭圆

.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>

箭头：

.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>

三角形：

.rencentle {
  width: 0;
  height: 0;
  border-left: 50px solid transparent;
  border-right: 50px solid transparent;
  border-bottom: 100px solid red;
}
<div class="rencentle"></div>