⚡ Physics Engine

A structured dark UI design system with semantic token naming, spring kinematics, and a built-in linter.

Most design systems are dictionaries — you look up a value and apply it. Physics Engine adds two things on top: semantic naming (tokens describe intent, not just value) and enforcement rules (a linter that validates Fitts Law, WCAG contrast, and geometric consistency). The tokens are hand-curated. The value is in what they mean and what the linter catches.

npx @dimkant/physics-engine lint DESIGN.md
npx @dimkant/physics-engine export --format tailwind DESIGN.md
npx @dimkant/physics-engine export --format swiftui DESIGN.md

The Idea

UI elements obey physical laws. A button press is not a CSS state change — it is an energy elevation and a physical compression. A card doesn't have a shadow — it has a low energy level that puts it above the void.

This metaphor makes design decisions self-explanatory to any AI agent. Instead of "use #3B82F6 for the primary button", you say: "primary actions are at Kinetic Peak (Level 3) and emit glow as a side effect of their energy state."

The agent knows not just what a color is — but when and why to use it.

DESIGN.md Format

Physics Engine uses the DESIGN.md format — YAML front matter for machine-readable tokens, markdown prose for the rationale.

---
name: My App
colors:
  void:     "#050505"   # Level 0 — Background
  surface:  "#111113"   # Level 1 — Cards, panels
  kinetic:  "#3B82F6"   # Level 3 — Primary actions, emits glow
  success:  "#22C55E"   # Confirmation, completion
  warning:  "#F59E0B"   # Non-blocking alerts
spacing:
  compact: "8px"        # 2× Base Unit
  optimal: "16px"       # 4× Base Unit
motion:
  micro:
    type: spring
    mass: 0.5
    stiffness: 500
    damping: 25
components:
  button-primary:
    backgroundColor: "{colors.kinetic}"
    textColor:       "{colors.kinetic-text}"
    height:          "44px"
    motion:          "{motion.micro}"
  button-primary-disabled:
    backgroundColor: "{colors.interactive}"
    textColor:       "{colors.surface-text-muted}"
    height:          "44px"
---

An AI agent reading this file knows: the button color, its disabled state, its animation spring parameters, its minimum touch size — without guessing any of it.

The Physics

Energy Levels (Color System)

Typography Scale

Spatial Mathematics

All dimensions derive from a single Base Unit: 4px.

Compact  =  2× =  8px  →  icon-to-text gap
Optimal  =  4× = 16px  →  standard component padding
Loose    =  6× = 24px  →  section spacing
Macro    = 12× = 48px  →  layout gaps

Topology Collapse (Border Radius)

Dynamic Radius = min(12px, height / 2)
Surface Radius = 32px

Radius is a function of geometry, not a designer's choice.

Kinematics (Spring Physics)

No ease-in-out. No linear. Physics Engine uses spring presets as machine-readable tokens:

motion:
  micro:                      # Buttons, toggles, chips
    type: spring
    mass: 0.5
    stiffness: 500
    damping: 25
  macro:                      # Modals, sidebars, drawers
    type: spring
    mass: 1.0
    stiffness: 250
    damping: 30
  tap-scale: 0.96

Data Visualization

Six perceptually distinct colors for charts and multi-series data: data-1 (#3B82F6) · data-2 (#8B5CF6) · data-3 (#10B981) · data-4 (#F59E0B) · data-5 (#EF4444) · data-6 (#06B6D4)

Accessibility

• Fitts Law — Every interactive element must be at least 44×44px
• Focus Ring — 2px solid {colors.kinetic}, offset 2px
• ARIA — All interactive elements carry semantic HTML and aria-* states

CLI

Install

npm install -g @dimkant/physics-engine
# or run without installing:
npx @dimkant/physics-engine lint DESIGN.md

lint — Validate your DESIGN.md

npx @dimkant/physics-engine lint DESIGN.md

{
  "findings": [
    {
      "rule": "fitts-law",
      "severity": "info",
      "path": "components.button-primary",
      "message": "height 44px meets Fitts Law minimum."
    }
  ],
  "summary": { "errors": 0, "warnings": 0, "info": 3 }
}

Exit code 1 if errors are found.

export — Convert to other formats

# Tailwind theme config
npx @dimkant/physics-engine export --format tailwind DESIGN.md > tailwind.config.js

# W3C Design Token Format (DTCG)
npx @dimkant/physics-engine export --format dtcg DESIGN.md > design_tokens.json

# SwiftUI Design System
npx @dimkant/physics-engine export --format swiftui DESIGN.md > DesignSystem.swift

spec — Print the specification

npx @dimkant/physics-engine spec

Programmatic API

import { lint } from '@dimkant/physics-engine/linter';
import { exportTokens } from '@dimkant/physics-engine/exporter';

const report = lint(designMdString);
console.log(report.findings);     // Finding[]
console.log(report.summary);      // { errors, warnings, info }
console.log(report.designSystem); // Parsed DesignSystem

const tailwind = exportTokens(designMdString, 'tailwind');
const dtcg     = exportTokens(designMdString, 'dtcg');
const swiftui  = exportTokens(designMdString, 'swiftui');

Generating UI with AI

Drop DESIGN.md into your AI agent's context and ask it to build UI. The agent derives every property from the file — no guessing.

Prompt:

Build a login form using this DESIGN.md. Use only values from the file.

What the agent knows without being told:

• Input backgrounds at Level 2 (#1F1F24)
• Focus state: Level 2.5 (#2A2A30) + 2px kinetic ring
• Submit button: Level 3 (#3B82F6) + glow + 44px height
• All padding multiples of 4px
• Spring physics (mass: 0.5, stiffness: 500) for all transitions
• Disabled state uses muted text on surface background

Linting Rules

Examples

Each example includes DESIGN.md, design_tokens.json, tailwind.config.js, and README.md.

Project Structure

design-physics-engine/
├── DESIGN.md              ← The design system spec (start here)
├── src/
│   ├── cli.ts             ← CLI entry point
│   ├── lint.ts            ← Linter (9 rules)
│   ├── export.ts          ← Export to Tailwind / DTCG / SwiftUI
│   └── parse.ts           ← DESIGN.md parser
├── examples/
│   ├── dark-command/
│   ├── kinetic-commerce/
│   ├── calm-focus/
│   └── material-3/        ← Google M3 encoded as Physics Engine
└── docs/
    └── spec.md            ← Full specification v1.1

Compatibility

Physics Engine's DESIGN.md is compatible with and extends @google-labs-code/design.md.

Physics Engine adds: motion tokens · success/warning colors · data viz palette · label/caption/code typography · component states (disabled, error, loading) · SwiftUI export · stricter linting (Fitts Law, energy-conservation, nested-radius-law).

npx @google-labs-code/design.md lint DESIGN.md   # Google's linter
npx @dimkant/physics-engine lint DESIGN.md        # Physics Engine (stricter)

Roadmap

• v1.1 — Motion token validation in linter · Framer Motion code generation
• v1.2 — OKLCH color space (L axis maps to Energy Levels)
• v2.0 — VS Code extension · Figma Variables sync

License

MIT ©2026 Dima Trubnikov