Have you tried enabling HTML5 shiv ?
Without this (or similar), IE8 will not be able to style elements that are new to HTML5 (e.g., <section> , <nav> , etc.). For me, selectivizr.js really allows Neat to work with IE8, but if you use HTML5 elements, even with selectivizr Neat will not be able to style them in IE8 without HTML5 shiv. (nb. This is not a problem with Neat per se - it is a more general problem that IE8 is a pre-HTML5 browser).
Effectively, selectivizr.js fixes problems with selectors that IE8 does not recognize, while HTML5 shiv fixes problems with unrecognized elements: if you use HTML5 elements, then for everything to work smoothly, you'll probably need both.
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