Google:  font-family: arial,sans-serif;
    Yahoo:  font: 13px/1.25 "Helvetica Neue",Helvetica,Arial;
    Apple:  font: 12px/18px "Lucida Grande", "Lucida Sans Unicode", Helvetica, Arial, Verdana, sans-serif;

    Baidu:  font: 12px arial;
    Weibo:  font: 12px/1.125 Arial,Helvetica,sans-serif;
    QQ:     font: 12px "宋体","Arial Narrow",HELVETICA;
    Sina:   font-family: "SimSun","宋体","Arial Narrow";
    163 :   font:12px/1.5 \5b8b\4f53,Arial,sans-serif;
    zhihu:  font-family: ‘Helvetica Neue‘,Helvetica,Arial,Sans-serif;


默认字体样式：
1、兼容性好
font-family: Helvetica,Tahoma,Arial,Sans-serif;
2、更接近设计
font-family: Geogia,"Times New Roman", Times, serif;