Customizing main_menu so that it shows nested elements with styling in Drupal 7 I have the following menu structure which i like to implement in Drupal 7 :

&lt;ul id="dropdown-menu" class="fixed"&gt;
    &lt;li&gt;&lt;a href="index.html"&gt;Home&lt;/a&gt;&lt;/li&gt;
    &lt;li&gt;&lt;a href="about.html"&gt;About&lt;/a&gt;
        &lt;ul class="sub-menu"&gt;
            &lt;li&gt;&lt;a href="about.html"&gt;About Us&lt;/a&gt;&lt;/li&gt;
            &lt;li&gt;&lt;a href="team.html"&gt;Team&lt;/a&gt;&lt;/li&gt;
        &lt;/ul&gt;
    &lt;/li&gt;
&lt;/ul&gt;


So far i have the base elements displaying correctly using :

&lt;?php 
print theme('links__system_main_menu', 
array('links' =&gt; $main_menu, 'attributes' =&gt; array('id' =&gt; 'dropdown-menu', 
'class' =&gt; array('fixed')))); 
?&gt;


Problems : 


It doesn't display nested elements
I can only control the styling of the first level but in my code i have to apply a subclass of 'sub-menu' according to my theme.


Can someone point me to a starting point ? Thanks
As far as I know, it's not possible to make theme('links__system_main_menu' [...]) display the nested elements. That suprised me, too...

One way to fix this: set up a region in the theme for the menu and put a menu block in there. This will display the nested elements, however styling the menu itself won't be much easier than before. theme_menu_tree() and theme_menu_link() hooks could be useful.

Also, check out the Menu block module.

p.s. I'm currently doing something similar that you do and it seems to be quite complicated for me, too, so I just summarized what I've already found.