Visually distinguish informational sidebar counters from action-required counters

Numeric badges in the left sidebar currently share the same visual treatment regardless of whether they represent something the host needs to act on (e.g., unread inbox items, reviews to leave, tasks assigned) or something purely informational (e.g., the "New" counter on Properties, which just indicates a listing was linked in the last 5 days and clears itself automatically). Because both badge types use the same style, hosts read every counter as "something requires my attention," open the section expecting an action item, and then can't find one.