🎨 Palette: Accessible and Semantic Navigation

[ISTEC-FOR340]

I've enhanced the project's accessibility and semantic structure with the following micro-UX improvements:

1. Semantic Navigation: Replaced non-semantic div elements and manual JavaScript navigation with proper <a> tags. This provides native keyboard support, better SEO, and a more robust user experience.
2. Focus Visibility: Added high-contrast :focus-visible styles using the design system's accent color. This ensures that keyboard users have clear visual feedback when navigating the site.
3. Accessibility Best Practices:
   • Set the lang="es" attribute on all pages to match the target audience and content.
   • Added aria-label="Volver al inicio" to the refactored back links.
   • Converted nested buttons within cards to <span> elements to avoid invalid nested interactive HTML.
4. Code Cleanup: Removed the redundant script.js as navigation is now handled natively by the browser.

These changes make the "Interactive Sketches" landing page and its subprojects more inclusive and intuitive without altering the original visual design.

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PR created automatically by Jules for task 12987352455878738979 started by @ISTEC-FOR340

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