Yep. On my first attempt after reading the spec (before posting this question here), I realize now that I was missing a descendent selector, which led me to think it would not work.
Now that I see, and with your helpful example, I’m good. Thanks for the nudge
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html lang="en" dir="ltr"><head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta http-equiv="Content-Language" content="en">
<title>OGS Nav</title>
<style>
div div {background:red;} // for ie6
div + div + div div{background:red;} //for the rest of them
</style>
</head><body>
<div>stuff</div>
<div>stuff</div>
<div>stuff<div>asdf</div></div>
</body></html>
although it’s not what you’ve asked
just so you know, > selector (selects an element that is a child of another element), + selector (selects an element that is a next sibling of another element) are not supported in ie6.