(feat): initial stuff

README.md

@@ -1,5 +1,59 @@
-# Quick Start
+# Methanium UI
 
-```
+```sh
 pnpm install https://git.methanium.net/methanium/ui/releases/download/latest/methanium-ui.tgz
 ```
+
+Import the stylesheet once, then add the provider at the application root:
+
+```tsx
+import "@methanium/ui/index.css";
+import { ThemeProvider } from "@methanium/ui";
+
+<ThemeProvider>{children}</ThemeProvider>;
+```
+
+## App Default
+
+Vite applications can choose their initial parent theme at build time:
+
+```ts
+import { methaniumUi } from "@methanium/ui/vite";
+
+export default defineConfig({
+  plugins: [methaniumUi({ defaultThemeId: "tensamin" })],
+});
+```
+
+The built-in parent themes are `tensamin`, `methanium`, and `secret`. Without
+the plugin or a provider override, the neutral base theme is used.
+Public Sans is bundled as the default typeface; users can switch to their
+platform's system font in the customizer.
+
+## Custom Themes
+
+Pass a typed manifest to `ThemeProvider` to add themes. Presets are ordinary
+CSS and remain fully editable after selection.
+
+```ts
+import { BUILT_IN_THEMES, defineThemes } from "@methanium/ui";
+
+export const themes = defineThemes([
+  ...BUILT_IN_THEMES,
+  {
+    id: "my-theme",
+    title: "My Theme",
+    logo: "/themes/my-logo.svg",
+    css: `:root[data-theme="my-theme"] { --primary: #ff4f91; }`,
+  },
+]);
+```
+
+Use `<ThemeCustomizer />` for all theme editing. `<ThemeSelector />` is its
+focused parent-theme selection control.
+
+## Onboarding
+
+Every `OnboardingStep` requires a `title`; the flow owns title rendering and
+focus. `<ThemeOnboardingPage />` applies choices immediately and prevents
+continuing until the user explicitly selects a theme.