效果图：

HTML代码：

 
 
 
 
 
 
 
 
 
 默认
 圆
 
 
 0.25
 0.5
 0.75
 1
 
 鼠标感应器(the mouse sensor)
 
 
 
 
 
 

CSS代码：

* {
 margin: 0;
 padding: 0;
 box-sizing: border-box;
}
body {
 position: absolute;
 text-align: center;
 height: 100%;
 width: 100%;
}
.main{
 position: relative;
 margin: 0 auto;
 height: 100%;
 background-color: rgb(48, 70, 82)
}
.main .content{
 position:absolute;
 display: inline-block;
 top:50%;
 left:50%;
 margin-left: -300px;
 margin-top: -150px;
 width: 600px;
 height: 300px;
 line-height: 300px;
 /*overflow: hidden;*/
 background: radial-gradient(ellipse farthest-corner, rgb(115, 176, 198) 0%, #888 100%);
 background: -webkit-radial-gradient(ellipse farthest-corner, rgb(115, 176, 198) 0%, #888 100%);
 box-shadow: 2px 3px 8px rgba(67, 50, 124 ,.6),0px 0px 8px rgba(67, 50, 124 ,.6);
}
.main .content .content-nav-top{
 display: none;
 position: absolute;
 margin-top: -50px;
 height: 50px;
 width: 300px; 
}
.main .content .content-nav-top >span{
 display: block;
 float: left;
 font-size: 16px;
 font-weight: normal;
 margin-right:1px;
 width: 50px;
 height: 50px; 
 line-height: 50px; 
 background-color: rgba(251, 214, 146,.3); 
 box-shadow: 0px 4px 13px rgb(222,222,222,1);
 cursor: pointer;
}
.main .content .content-nav-top >span:nth-child(1){
 border-radius:0 ; 
}
.main .content .content-nav-top >span:nth-child(2){
 border-radius:50% ; 
}
.main .content .content-nav-top >span:nth-child(3){
 border-radius:0; 
}
.main .content .content-nav-top >span:nth-child(4){
 border-radius: 50% ; 
}
.main .content .content-nav-left{
 display: none;
 position: absolute;
 margin-left: -50px;
 width: 50px;
 height: 300px; 
}
.main .content .content-nav-left >span{
 display: block;
 font-size: 16px;
 font-weight: normal;
 margin-bottom:1px;
 width: 50px;
 height: 50px; 
 line-height: 50px; 
 background-color: rgb(85, 145, 140); 
 box-shadow: 0px 4px 13px rgb(222,222,222,1);
 border-radius:50% 0 0 50% ; 
 cursor: pointer;
}
.box{
 position: relative;
 float: left;
 width: 49.9%;
 height: 100%;
 border-right-style: solid;
 border-right-width: 1px;
 border-right-color: rgba(211,211,211,.5);
 color:rgb(99, 84, 168);
 text-shadow: 0px 1px 0px #888,1px 0px 0px #888,0px 0px 1px #888;
 }
.block{
 float: right;
 width: 50%;
 height: 100%;
}

JS代码:

这里的鼠标箭头也可换成自己喜欢的图标，模拟鼠标区域的颜色也可自由变换，模拟区域的效果也可是点状的，也可以是线状的，动画效果等等，这个自由发挥吧。