See `requirements.md`; requirement ids (R1.1, …) are referenced below.
## Decisions
| Decision | Reason |
|---|---|
| The web app writes the theme's id to a `mancala_theme` cookie; a small script in the login theme reads it and puts the theme's class on `<html>` | Keycloak's pages are on another origin (`localhost:8080`, `auth.playmancala.app`), so they cannot read the app's `localStorage`. Cookies are shared: host-only cookies across the ports of `localhost`, and a cookie for `playmancala.app` with its subdomains (R1.2). |
| The script runs in `<head>`, before the page is drawn | No flash of another theme. |
| Without the cookie, the script picks Ceviz or Yeşim from `prefers-color-scheme` (R1.3) | The app's default theme is Ceviz (dark); Yeşim is its only light theme. |
| `darkMode=false` in the theme; the script adds PatternFly's `pf-v5-theme-dark` itself for the dark themes | Keycloak's own dark mode follows the system and would fight the chosen theme. |
| The theme stays a stylesheet on top of `keycloak.v2`, now with the three themes' tokens copied from `apps/frontend/src/styles/app.css` | Templates stay Keycloak's, so upgrades need no template changes. |
| The logo and the small board on the card are masks filled with the theme's colors | One image each for all three themes. |
| The app's name comes from CSS by the page's language | The realm's display name is one string; the header shows "Köçürme" for Turkish and "Mancala" otherwise, like the web app. |
| Notyf stays for messages, configured for the top centre and restyled with the theme's variables (R2) | It is used from plain functions (`Util.checkConnectionAndMaybeAlert`), not only components; a React toast would need a context everywhere. |