I just checked it. The markers are level one. Once you are at level two left and right stays on level two. You get out of level two by a next/previous page. Well handy to know. I adjust my script to generate 2 levels in the ncx file.
Now I wonder how my toc.html gets nicely indented
I expected something like
but I get
Do i need special markup I did
<div> <a href="#l1">Makefiles</a>
<div> <a href="#l1-1">Rules</a></div>
<div> <a href="#l1-2">Recursive</a></div>
Or is the toc always flat?