- Revised title and meta description to better reflect the app's purpose and target audience.
- Enhanced layout and styling of ad preview components for improved user experience.
- Adjusted padding, margins, and background colors for better visual consistency.
- Updated section headers and text to clarify ad placement and audience targeting.

- Added new section header styles for ad previews to improve layout and visual hierarchy.
- Refactored HTML structure for sponsor and copy sections to align with updated design specifications.
- Adjusted padding and margins for better spacing and consistency across ad components.

- Introduced new CSS variables for ad colors and styles to improve visual consistency.
- Refactored ad preview components to align with in-app AdView design, enhancing layout and responsiveness.
- Updated HTML structure for sponsor and copy sections to improve clarity and accessibility.
- Adjusted button styles for better user interaction and visual appeal.

Revert renderAdCards to pre-regression imperative append flow that previously
rendered cards reliably in production browsers. Keep safe stats formatting and
null guard so malformed PostHog rows cannot crash card rendering.

Serve calendar UI assets from /vendor/flatpickr on gymtracker; Safari/WebKit
'permission' failures often trace to blocked jsDelivr or overly broad
Access paths. Document narrowing Access or bypass for /favicon and /vendor.

Note: flatpickr.min.Js is force-added (repo .gitignore ignores *.min.js).

- Normalize pathnames (trailing slashes) so /api/admin/ads/ hits the Worker
- adsArrayFromKvJson: accept one ad object stored under KV key ads
- renderAdCards: clear #adCards then appendChild(fragment); avoid replaceChildren
quirks on some WebKit builds; guard missing #adCards

- Strong HTML response Cache-Control plus CDN-Cache-Control: no-store
- Meta no-cache tags and build comment for source verification
- Build ad list in a DocumentFragment; replaceChildren only on success
so a failed PostHog re-render cannot wipe cards (stale JS / errors)
- Remove height:100% on card wrappers that could collapse grid sizing

PostHog stats or partial rows could leave ctr_percent undefined, which
threw during renderAdCards and hid all cards after group headers.