iOS WebKit silently degrades position: sticky to static on direct
flex/grid children of <body>, so the sticky nav was breaking on
mobile. Wrapping everything below the nav in a .page-shell flex
column keeps the sticky-footer math out of body { } and restores
sticky behaviour across browsers. The essay-frontmatter hoisted in
the Marks II commit becomes a body-level sibling of .page-shell so
its monogram and epistemic-figure columns can span viewport width.
* templates/default.html wraps $body$ + footer in .page-shell.
* static/css/layout.css moves the flex-column + min-height math from
body to .page-shell; the body > header rule now excludes
.essay-frontmatter so the essay header does not inherit nav chrome
(sticky, nav-bg, border-bottom).
* static/css/base.css drops the html/body overflow-x: clip — the
page-shell wrapper handles horizontal containment and clipping at
the viewport level was interfering with position: sticky.
* static/css/reading.css updates its #markdownBody centering selector
to match .page-shell > #markdownBody.
* static/css/components.css makes the TOC outline scrollable when
it overflows: bounded max-height tied to the sticky budget plus a
thin themed scrollbar, with overflow: hidden preserved for the
collapse transition.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>