CSS3 submenu 子菜单不能正常工作

Question

我已经创建了一个用于创建菜单的 css3 样式表，在主菜单的子菜单中是正确的，但在创建子菜单之后。子菜单的子元素无法正常工作。

我想将子菜单的子菜单移动到父级的底部，我可以将鼠标光标移动到子级

JSFIDDLE

HTML:

<ul id="nav" class="nav" style='margin-right:0px;padding-right:0px;padding-top:0px;height:30px;'>
    <li><a>MAIN MENU</a>
        <ul>
            <li><a href="#tab1">MENU 1</a>
                <ul>
                    <li><a>SUBMENU</a></li>
                </ul>
            </li>
            <li><a href="#tab2">MENU 2</a></li>
            <li><a href="#tab3">MENU 3</a></li>
        </ul>       
    </li>
</ul>

CSS3:

#nav {
    color: #fff;
    margin: 0;
    line-height: 100%;
    padding-top: 4px;
    padding-bottom: 4px;
    height: 33px;
    background: -moz-linear-gradient(center top , #5E9AE2, #3570B8) repeat scroll 0 0 transparent;
    z-index: 10000;
}
#nav li {
    margin: 0pt 5px;
    padding: 2pt 0pt 5px;
    float: right;
    position: relative;
    list-style: none outside none;
    z-index: 10000;
    cursor: pointer;
}
#nav a {
    color: #fff !important;
    text-decoration: none;
    display: block;
    padding: 9px 10px;
    margin-right: 0pt;
    border-radius: 5px 5px 5px 5px;
    font-weight: normal;
    z-index: 100000;
    cursor: pointer;
}
#nav .current a, #nav li:hover > a {
    z-index: 100000;
    background: #fff ! important;
    color: #000 ! important;
    box-shadow: 0pt 1px 1px rgba(0, 0, 0, 0.2);
}
#nav ul li:hover a, #nav li:hover li a {
    z-index: 100000;
    background: none repeat scroll 0% 0% transparent;
    color: #000 ! important;
    box-shadow: none;
}
#nav ul a:hover {
    background: -moz-linear-gradient(center top , rgb(198, 71, 53), rgb(147, 35, 19)) repeat scroll 0% 0% transparent ! important;
    background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,#c44634), color-stop(100%,#952414)) repeat scroll 0% 0% transparent ! important; /* Chrome,Safari4+ */
    background: -webkit-linear-gradient(top,  #c44634 0%,#952414 100%) repeat scroll 0% 0% transparent ! important; /* Chrome10+,Safari5.1+ */
    background: -o-linear-gradient(top,  #c44634 0%,#952414 100%) repeat scroll 0% 0% transparent ! important; /* Opera 11.10+ */
    background: -ms-linear-gradient(top,  #c44634 0%,#952414 100%) repeat scroll 0% 0% transparent ! important; /* IE10+ */
    background: linear-gradient(to bottom,  #c44634 0%,#952414 100%) repeat scroll 0% 0% transparent ! important; /* W3C */
    filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#c44634', endColorstr='#952414',GradientType=0 ) ! important; /* IE6-9 */
    color: rgb(255, 255, 255) ! important;
    border-radius: 0pt 0pt 0pt 0pt;
    text-shadow: 0pt 1px 1px rgba(0, 0, 0, 0.1);
    cursor: pointer;
}
#nav ul {
    background: #ffffff; /* Old browsers */
    background: -moz-linear-gradient(top,  #ffffff 0%, #cfcfcf 100%); /* FF3.6+ */
    background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,#ffffff), color-stop(100%,#cfcfcf)); /* Chrome,Safari4+ */
    background: -webkit-linear-gradient(top,  #ffffff 0%,#cfcfcf 100%); /* Chrome10+,Safari5.1+ */
    background: -o-linear-gradient(top,  #ffffff 0%,#cfcfcf 100%); /* Opera 11.10+ */
    background: -ms-linear-gradient(top,  #ffffff 0%,#cfcfcf 100%); /* IE10+ */
    background: linear-gradient(to bottom,  #ffffff 0%,#cfcfcf 100%); /* W3C */
    filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#ffffff', endColorstr='#cfcfcf',GradientType=0 ); /* IE6-9 */
    display: none;
    margin: 0pt;
    padding: 0pt;
    text-align: right;
    width: 180px;/*طول منو*/
    position: absolute;
    top: 35px;
    right: 0pt;
    border-radius: 5px 5px 5px 5px;
    direction: rtl;
    box-shadow: 0pt 1px 3px rgba(0, 0, 0, 0.3);
}
#nav li:hover > ul {
    display: block;
}
#nav ul li {
    float: none;
    margin: 0pt;
    padding: 0pt;
}
#nav ul li ul{
    float: none;
    margin-top:28px;
    margin-right: 180px;
    top: 0px;
}
#nav ul li ul li:first-child > a {
    border-radius: 5px 5px 5px 5px;

    behavior: url('./css/PIE.htc');
}
#nav ul li ul li:last-child > a {
    border-radius: 5px 5px 5px 5px;
    behavior: url('./css/PIE.htc');
}

#nav ul a {
    font-weight: normal;
    text-shadow: 0pt 1px 1px rgba(255, 255, 255, 0.898);
}
#nav ul li:first-child > a {
    border-top-left-radius: 5px;
    border-top-right-radius: 5px;
    border-radius: 5px 5px 0px 0px;
    behavior: url('./css/PIE.htc');
}
#nav ul li:last-child > a {
    border-bottom-left-radius: 5px;
    border-bottom-right-radius: 5px;
    border-radius: 0px 0px 5px 5px;
    behavior: url('./css/PIE.htc');
}
#nav:after {
    z-index: 100000;
    content: ".";
    display: block;
    clear: both;
    visibility: hidden;
    line-height: 0pt;
    height: 0pt;
}

这个方法没有问题，但我想要任何子菜单，但无法修复它。请帮助我，

Answer 1

#nav ul li ul {
    float: none;
    margin-right: 180px;
    margin-top: 28px; /* <-- this is causing issue */
    top: 0;
}