自定义有序列表`

[semi-xi]

ol {
margin-left:0px;  
    padding-left:0px;  
    counter-reset:li; 
}
ol > li{
    position:relative;
    margin:0 0 6px 2em;
    list-style:none;
}
ol >li:before{
    content:counter(li);
    counter-increment:li;
    position:absolute;
    color:red;
}