无法在悬停时隐藏和显示第3个菜单项

Question

这是我的3级菜单的CSS。我可以隐藏第3级，但是我无法在第2级悬停时显示它。这是一个wordpress侧面菜单功能。

ul.sidebar-navi-na {
    width:auto;
    background:#8f9044;
    border-right: 1px solid #d8d8d8;
    padding:5px 15px 9px 0px;
    z-index:200;
    list-style:none;
    margin:5px 25px 0 0;
}
ul.sidebar-navi-na li.last {
    border-bottom:0px;
}
ul.sidebar-navi-na li a {
    position:relative;
    display:block;
    width:95%;
    float:none;
    padding:2px 0px;
    margin:0px;
    color:#888;
    z-index:191 !important;
    text-decoration:none;
    text-transform:none;
    font-weight:normal;
    border-bottom:1px solid #e9e9e9;
    -webkit-transition: all 0.2s ease 0s;
    -moz-transition: all 0.2s ease 0s;
    -o-transition: all 0.2s ease 0s;
    transition: all 0.2s ease 0s;
    font-size:15px;
}
ul.sidebar-navi-na li a:hover {
    color:#000;
    ?>;
    text-decoration:none;
}
ul.sidebar-navi-na li {
    margin:5px;
    display:block;
    width:100%;
}
ul.sidebar-navi-na ul.sub-menu {
    margin-left:10px;
    display:none;
}
ul.sidebar-navi-na li.current_page_item ul, ul.sidebar-navi-na li.current_page_ancestor ul, ul.sidebar-navi-nali.current_page_parent ul {
    display:block;
}
ul.sidebar-navi-na li a {
    color:#000;
}
ul.sidebar-navi-na li ul.sub-menu a:active {
    margin-bottom: 0;
    background:#fff;
    width:100%;
}
ul.sidebar-navi-na li ul.sub-menu {
    margin-bottom: 0;
    background:#b0b152;
    width:100%;
}
ul.sidebar-navi-na li ul.sub-menu a:hover {
    margin-bottom: 0;
    background:#fff;
    width:100%;
}
ul.sidebar-navi-na li ul.sub-menu .sub-menu a:active {
    margin-bottom: 0;
    background:#fff;
    width:95%;
}
ul.sidebar-navi-na li ul.sub-menu .sub-menu {
    margin-bottom: 0;
    background:#b0b152;
    width:95%;
}
ul.sidebar-navi-na li ul.sub-menu .sub-menu a:hover {
    margin-bottom: 0;
    background:#fff;
    width:95%;
}