微信小程序wxss如何引用外部CSS文件以及iconfont

````
@font-face {font-family: "iconfont";
 src: url('iconfont.eot?t=1485242349767'); / IE9/
 src: url('iconfont.eot?t=1485242349767#iefix') format('embedded-opentype'), / IE6-IE8 /
 url('iconfont.woff?t=1485242349767') format('woff'), / chrome, firefox /
 url('iconfont.ttf?t=1485242349767') format('truetype'), / chrome, firefox, opera, Safari, Android, iOS 4.2+/
 url('iconfont.svg?t=1485242349767#iconfont') format('svg'); / iOS 4.1- /
}

.iconfont {
 font-family:"iconfont" !important;
 font-size:16px;
 font-style:normal;
 -webkit-font-smoothing: antialiased;
 -moz-osx-font-smoothing: grayscale;
}

````