Ordering barriers
An ordering barrier keeps several head nodes together while telling the head optimiser where the block belongs:
<!-- sklair:ordering-barrier treat-as=stylesheet -->
<link rel="stylesheet" href="/fonts.css">
<style>.icon { font-family: Sklair Icons; }</style>
<!-- sklair:ordering-barrier-end -->
Allowed treat-as values are:
charsethttp-equivviewportresource-hinttitlestylesheetscriptanalyticsdont-care
The complete block is ordered at that priority. Its internal node order remains intact, and nodes inside it are not individually deduplicated. Barriers cannot nest. An unknown type, unmatched end, or unclosed barrier fails compilation.
Use barriers when two head nodes have a real ordering relationship which ordinary per-element classification cannot express. See Head processing for the full priority order.