This snippet creates a menu where every menuitem on the 1.level has a own id. Using this id you can format the submenu with css selectors.

In this example a nested unordered list is created where to every mainmenupoint the css id menuitemUID is addet. UID is here the unique ID of the page.

lib.menu=HMENU
lib.menu{
  1 = TMENU
  1.wrap=<ul>|</ul>
  1.NO{
    allWrap.insertData=1
            # change  to allWrap=<li id="menuitem{field:title}">| if you want the title instead of the uid as css id
    allWrap=<li id="menuitem{field:uid}">|
    wrapItemAndSub = |</li>
  }
   
  2<.1
  2.NO.allWrap=|
  2.NO.wrapItemAndSub=<li>|</li>
}