Pill-shaped action button in the Qubera house style — use for every call-to-action and primary/secondary action.

```jsx
<Button variant="primary" arrow href="#access">Request access</Button>
<Button variant="ghost" icon={<PlayIcon />}>Watch demo</Button>
```

Variants: `primary` (navy fill, default), `ghost` (bordered, light bg), `onDark` (white fill — over ink-navy), `ghostDark` (bordered — over ink-navy). Sizes: `sm` / `md` / `lg`. Set `arrow` for the trailing chevron that slides on hover; pass `icon` for a leading glyph. Provide `href` to render an `<a>`. Headlines and buttons are the only places navy fills large areas — keep one primary button per view.