SOURCE

<div></div>

html,body { /*这里没用*/
                width: 100%;
                height: 100%;
                margin: 0;
                padding: 0;
            }
            div {
                width:0;
                color:hotpink;
                border:160px solid transparent;
                border-top: 160px solid;
                box-shadow: 0 -240px 0 -80px;
                /*下面的只是垂直居中而已*/
                margin: 0 auto; 
                position: relative; 
                top: 50%; 
                margin-top: -60px;
            }