Improve Lighthouse and Core Web Vitals metrics

Current site baseline

Based on the current measurements for the balldecor.ru homepage:

• Performance: 52
• Accessibility: 57
• Best Practices: 74
• SEO: 100

The SEO score is high, but the other metrics are noticeably lagging. During the migration to HAIH, this must be used as a measurable technical baseline to avoid reproducing legacy issues.

Objective

Achieve significantly better performance, accessibility, and best practices scores on the new version of the site without sacrificing SEO, functionality, or marketing scenarios.

Action items

1. Establish a reproducible Lighthouse baseline for the homepage and several key commercial pages in both mobile and desktop modes.
2. Analyze the main causes of Performance losses:
   • LCP and heavy hero content;
   • image sizes and formats;
   • excess JavaScript/CSS;
   • render-blocking resources and third-party scripts;
   • fonts;
   • CLS;
   • TBT/INP;
   • server response time and caching.
3. Optimize images: modern formats, responsive sizes/srcset, correct dimensions, lazy loading for off-screen images, and preloading only truly critical resources.
4. Minimize client-side JS and hydration where SSR/plain HTML is sufficient; avoid dragging in heavy libraries unnecessarily.
5. Configure static asset caching, compression, immutable assets, and a CDN/cache layer if used in the HAIH deployment.
6. Fix accessibility issues:
   • contrast;
   • correct labels/ARIA;
   • semantic heading structure;
   • keyboard navigation/focus;
   • touch target sizes;
   • alt texts;
   • form and calculator accessibility.
7. Fix Best Practices: console errors, outdated/unsafe APIs, resource loading issues, security headers, and other Lighthouse warnings.
8. Prevent SEO degradation: SSR, indexability, metadata, canonical tags, structured data, and internal links must be preserved.
9. Add Lighthouse/PageSpeed checks to the final smoke test before launch and use them for regression control after major changes.

Target benchmarks

For key pages of the new version, aim for:

• Performance: 90+
• Accessibility: 95+
• Best Practices: 95+
• SEO: 95–100

Targets must not be achieved by removing business-critical features or artificially simplifying the page.

Definition of done

Key pages of the new version consistently and noticeably outperform the legacy baseline, critical Core Web Vitals are within the acceptable range, and major Lighthouse issues are resolved and do not recur with subsequent changes.