On phones the footer's progress cell rendered the full chapter title (e.g. 'Long Chapter Name · 5 / 12') in a div with no max-width or nowrap, so the text wrapped to multiple lines and ballooned the bottom bar. Combined with viewport offsets that were computed from assumed pixel heights with ~0px margin, the book text slipped underneath the bars.
Chapter label in footer: split #progress-display into two spans (progressLabel hidden on mobile via 'hidden sm:inline', progressMain always shown) and cap it with 'truncate whitespace-nowrap max-w-[5rem] sm:max-w-none' so it can never wrap or grow the bar. Phones now show just '5 / 12'; larger screens keep 'Chapter · 5 / 12'.
Viewport offset: replace the fragile hardcoded calc() with runtime measurement. Gave the chrome bars ids (reader-topbar/reader-bottombar) and added updateViewportInsets(), which sets #reader-viewport top/bottom from each bar's real offsetHeight (which already includes env(safe-area-inset-*) padding) plus a 6px margin. It runs on init and refreshes on resize, orientationchange, and via a ResizeObserver, so the content area tracks the actual chrome height on any DPI, notch, home-indicator, or zoom level instead of guessing.
Refactored formatProgress into formatProgressParts (returns {label, main}; only chapter mode sets a label) with a setProgress() helper wiring progressLabel/progressMain/progressText across the relocate, cycleProgressMode, and applyProgressMode call sites. Rebuilt reader_templ.go and style.css.
john-okeefe