鼠标移到导行文字上不会变颜色？？？
.nav_mid_left a:link,.nav_mid_left a:visited
{
text-decoration:none;
color:#fff;
font-size:16px;
font-family:"微软雅黑";
}
.nav_mid_left a:hover,.nav_mid_left a:active;
{
text-decoration:none;
color:#FF0;
font-size:16px;
font-family:"微软雅黑";
}
