Indented HTML tags with :not() aren't highlighted correctly

[jsit]

a:not(:hover) {
}

.class {
	a {
	}
	a:not(:hover) {
	}
}

Minimal ~/.vimrc:

set nocompatible
filetype plugin on
filetype indent on
syntax on
set runtimepath+=~/.vim/bundle/vim-haml

a:not(:hover)
| |
| +-- sassCssAttribute
+---- sassProperty