...OVERVIEW...
What it is
FirmaUY is a set of open-source tools for signing and verifying documents with the Uruguayan electronic ID card. The website is the front door: one static Spanish page, no build step, no dependencies, published from the repository root.
I contributed the light/dark theme and the details around it: the toggle, the transition between themes, light and dark screenshots, responsive behavior, external links that open in a new tab, and a pass over colors and typography.
...MY CONTRIBUTION...
What I worked on
The site had to feel as considered as the desktop app it presents. My changes were visual and interaction work, made directly on the static page.
Light and dark mode
Added a theme toggle that respects the visitor's choice, persists it, and swaps the screenshots to match. The page ships both light and dark image sets, so the theme is real rather than a CSS filter over one set.
The transition
Built the theme switch transition: a 300 ms cross-fade of background, text and border colors, skipped under prefers-reduced-motion so the switch is instant instead of animated.
Responsive pass
Adjusted the layout and typography so the page reads well on a phone, not just a desktop browser.
Visual polish
Changed colors and type, refined spacing and details, and made external links open in a new tab so the page does not lose the reader.
The website is maintained by Carlos Planchón and its repository is private. The public FirmaUY project is linked above.