Design System Tokens from a Brand Brief

Act as a design systems lead. Create a starter design token set for {{brand_name}}, a brand that should feel {{brand_personality}}. Existing brand colour: {{base_colour}}. The tokens will be used on: {{platforms}}.

Requirements:
- Colour: a 10-step tonal scale (50–900) for the brand colour and for a neutral grey, plus semantic tokens that reference them: color.bg, color.surface, color.border, color.text, color.text-muted, color.accent, color.accent-hover, color.on-accent, color.success, color.warning, color.danger, color.focus. Provide a light theme and a dark theme. For every text/background pair, state the WCAG contrast ratio; body text must be at least 4.5:1.
- Typography: font families (free fonts), a modular scale with ratio 1.25 from 16px (list each step in px and rem), line heights, weights and letter spacing per step.
- Spacing: space.0 to space.12 on a 4px base (0, 4, 8, 12, 16, 24, 32, 40, 48, 64, 80, 96, 128).
- Radius: none, sm, md, lg, full, with px values and where each is used.
- Shadow: three elevation levels as CSS box-shadow values, tuned for both themes.
- Motion: duration.fast, duration.base, duration.slow in ms, and three easing curves (standard, enter, exit) as cubic-bezier values. Include a reduced-motion rule.

Output format:
1. A short rationale (max 120 words) explaining how the tokens express the personality.
2. The tokens as one JSON object following the W3C Design Tokens format ($value, $type).
3. The same tokens as CSS custom properties under :root and [data-theme="dark"].
4. A table of every text/background pair with its contrast ratio and pass/fail for AA.

Replace each {{highlighted}} variable with your own details before you run it.