Dificuldade para criar 3º nivel em menu

[alanmm]

Olá pessoal, andei pesquisando aqui no fórum uma solução para meu problema, mas as alternativas que tentei não resolveram o caso. Poderiam me dar uma ajudinha aqui?

Quero criar um terceiro nível em meu menu, especialmente no marcador "Download", para que eu possa, por exemplo, dar categorias de downloads como "material acadêmico, etc...".

<div class='top-nav'>
<div id='menu-dropdown'>
<ul id='topmobilemenu'>
   <li><a expr:href='data:blog.homepageUrl'><span><i class='icon-home'/></span></a></li>
   
<li class='has-sub'>
<a href='#'><span>Tecnologia</span></a>
      <ul>
         <li><a href='#'><span>Notícias</span></a></li>
<li><a href='#'><span>Downloads</span></a></li>
         <li class='last'><a href='#'><span>Products</span></a></li>
      </ul>
 </li>




   <li class='has-sub'>
<a href='#'><span>Negócios</span></a>
      <ul>
         <li><a href='#'><span>Marketing</span></a></li>
         <li class='last'><a href='#'><span>Location</span></a></li>
      </ul>
   </li>




   <li class='last'><a href='#'><span>Fashion</span></a></li>
   <li class='last'><a href='#'><span>Lifestyle</span></a></li>
  </ul>
</div>
<ul class='social-icons float-right'>
<li class='facebook'><a href='http://facebook.com' target='_blank' title='Facebook'>   <i class='icon-facebook'/>   </a></li> 
    <li class='twitter'><a href='https://twitter.com' target='_blank' title='Twitter'>     <i class='icon-twitter'/>     </a></li>
    <li class='gplus'><a href='https://plus.google.com' target='_blank' title='Google plus'>      <i class='icon-google-plus'/>       </a></li>


</ul>
</div>   
    <div class='clear'/> 

E o CSS pra ele é: (Vou colando a medida que eu for localizando no template)

#menu-dropdown {
max-width: 650px;
float: left;
}

#menu-dropdown {
  border: 0px;
  margin: 0px auto;
  padding: 0px;
  font-size: 14px;
  font-weight: bold;
  width:100%;
  max-width:750px;
  float:left;
}
#menu-dropdown ul {
  background: #333333;
  height: 45px;
  list-style: none;
  margin: 0;
  padding: 0;
}




#menu-dropdown li {
  float: left;
  padding: 0px;
}
#menu-dropdown li a {
  background: #333333 url('http://4.bp.blogspot.com/-eRuYGIJ6kZU/Un8xjrEuaUI/AAAAAAAABto/rEx77zt-lr4/s1600/seperator.gif') center right no-repeat;
  display: block;
  font-weight: 400;
  line-height: 45px;
  margin: 0px;
  padding: 0px 15px;
  text-align: center;
  text-decoration: none;
  font-family: Oswald, arial, Georgia, serif;
  text-transform: uppercase;
  font-size:15px;
}
#menu-dropdown > ul > li > a {
  color: #cccccc;
}
#menu-dropdown ul ul a {
  color: #cccccc;
}
#menu-dropdown li > a:hover,
#menu-dropdown ul li:hover > a {
  background: $(primary.color) url('http://2.bp.blogspot.com/-OIz_gMAJc6M/Un8xjibyHrI/AAAAAAAABt8/cJcD57RyXXY/s1600/hover.png') bottom center no-repeat;
  color: #FFFFFF;
  text-decoration: none;
}
#menu-dropdown li > a i{
  color: #FFFFFF;
  }


#menu-dropdown li ul {
  background: #333333;
  display: none;
  height: auto;
  padding: 0px;
  margin: 0px;
  border: 0px;
  position: absolute;
  width: 225px;
  z-index: 200;
  /*top:1em;
/*left:0;*/


}
#menu-dropdown li:hover ul {
  display: block;
}
#menu-dropdown li li {
  background: url('http://2.bp.blogspot.com/-62RZ4E3cHS8/Un8xkLqHRaI/AAAAAAAABt0/RqGVZ3Xy1Hs/s1600/sub_sep.gif') bottom left no-repeat;
  display: block;
  float: none;
  margin: 0px;
  padding: 0px;
  width: 225px;
}
#menu-dropdown li:hover li a {
  background: none;
}
#menu-dropdown li ul a {
  display: block;
  height: 35px;
  line-height:35px;
  font-size: 12px;
  font-style: normal;
  margin: 0px;
  padding: 0px 10px 0px 15px;
  text-align: left;
}
#menu-dropdown li ul a:hover,
#menu-dropdown li ul li:hover > a {
  background: $(primary.color) url('http://1.bp.blogspot.com/-xW_sOqCx39k/Un8xjlYSKqI/AAAAAAAABts/LJqXWuWTJME/s1600/hover_sub.png') center left no-repeat;
  border: 0px;
  color: #ffffff;
  text-decoration: none;
}
#menu-dropdown p {
  clear: left;
}

Em anexo segue um print do menu atual.