/* Session-aware nav — shared across every portal page that renders the "Log in" button (the landing page, the guides layout and the API reference), loaded as /_/css/session-nav.css alongside /_/js/session-nav.js. Carries the profile-chip component styles the script renders, plus the progressive-enhancement rule that hides the server-rendered "Log in" button until the session probe resolves (so an authenticated visitor never sees a "Log in" flash before the chip appears). These rules used to live only in the landing page's inline