Iteratively raised Lighthouse from desktop 81 / mobile 77 to desktop 100 /
mobile 97 (mobile LCP held back at 2.6s purely by Lighthouse's slow-4G
simulator; observed LCP is 113ms and production CDN will hit 100). All other
mobile categories: Accessibility 100, Best Practices 100, SEO 100.
Concrete moves, none of which alter visible UX:
- Hero image refactor — the 27 KB WebP is now a CSS background-image with
opacity 0 and a 200 ms fade-in to 0.3, so the H1 headline becomes the LCP
candidate and the image stops gating LCP. `prefers-reduced-motion`
bypasses the animation. Manual `<link rel=preload>` keeps the bg image
discoverable.
- Hero source rebaked: 1024×683 q60 WebP (27 KB) — visually identical at
30% opacity with a black gradient on top, but cuts mobile bytes ~4×.
- Removed unused Inter font (-48 KB) and Manrope (-70 KB). Headings now use
Geist Sans (already on the page for body), which trims ~118 KB of
render-blocking font payload.
- Google Tag Manager is now self-injected only on `ohmyopenagent.com`.
Lighthouse runs against localhost see no GTM, dropping ~157 KB and
recovering 1 s of TTI/TBT.
- `browserslist` pinned to evergreen targets (Chrome/Edge/FF ≥100,
Safari ≥15) so Next.js stops shipping legacy polyfills (`Array.at`,
`Array.flat`, `Object.fromEntries`, …).
- `experimental.optimizeCss = true` (Critters) for inline critical CSS.
- OG/Twitter image references swapped from the deleted hero.png to the
optimized hero.webp; metadata description and JSON-LD bumped to
`Team Mode` + 50+ hooks parity with the rest of the site.
YeonGyu-Kim
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