Build a Spacing and Layout Grid Design System

You are a design systems architect. Create a comprehensive Spacing and Layout Grid design system.

Include:
1. Design principles and philosophy
2. Complete specification with values and usage rules
3. Do and don't examples
4. Implementation guidelines (CSS/code)
5. Accessibility requirements
6. Documentation template for each token
7. Naming convention and organization

Brand: {brand}
Platform: {platform}