CSS删除在Internet Explorer上的项目符号

我在Internet Explorer中遇到了一个问题。我已经试图删除双重显示的子弹在ie，但我不知道为什么他们总是显示。在Internet Explorer 11中，它显示我自己的图标（一个绿色的钩子）和从浏览器生成的图标。我想保持绿色的钩子，并希望删除灰色的子弹。请查看此处。
如果您没有Internet Explorer，请查看我的。非常感谢！

I have a bullet points issue in Internet Explorer. I already tried to remove the doubled displayed bullets in ie, but I can't figured out why they always be displayed. In Internet Explorer 11 it shows my own icon (a green hook) and the generated icon from the browser. I want to keep the green hook and would like remove the gray bullets. Please take a look here. If you don't have Internet Explorer, please take a look at my . Thanks!

我的CSS代码生成子弹：

My CSS Code to generate the bullets:

ul,li, .nav ul, .nav li {
    list-style:none;
    list-style-type: none;
    list-style-position:inside;
    margin:0;
    padding:0;
}
.content ul{list-style:none;margin-left:0;padding-left:0em;text-indent:0em;}
.content ul li:before{
    content:'';
    background:url(http://www.deutsch-vietnamesisch-dolmetscher.com/i/haken-gruen.png) no-repeat;
    background-position:left center;
    padding:0 0 0 20px;
    margin:0 0px 0 0;
    list-style:none;
    white-space:normal
}
.content ul {padding: 0 0 0 15px;}
.content ul li ul {padding: 0 0 0 15px;}
.content ul li.list:before{background: none;}