html, body {
    padding: 0px;
    margin: 0px;
    background: #fff;
    -moz-user-select: -moz-none;
    -moz-user-select: none;
    -o-user-select: none;
    -khtml-user-select: none; /* you could also put this in a class */
    -webkit-user-select: none; /* and add the CSS class here instead */
    -ms-user-select: none;
    user-select: none; /**½ûֹѡÖÐÎÄ×Ö*/
}

.nav_item {
    text-align:center;
    font-size:24px;
    padding-top:45px;
}

.nav_item_height_60px {
    height:60px;
}

nav_item_height_15px {
    height:30px;
}

.nav_item_height_10px {
    height:10px;
}

.list_item {
    padding-top:8px;
    font-size:16px;
}

.list_item_download{
    width:100px;
    text-align: center;
    /*font-weight:bold;*/
    float:right;
    /*background-color:#444;
    color:white;*/
    border-radius:3px;
}