Design System Planning

Design System Planning

Plan and architect design systems for consistent, scalable user interfaces.

MANDATORY: Skill Loading First

Before answering ANY design system question:

1. Use established design system methodology (Nathan Curtis, Brad Frost)
2. Base all guidance on validated design system practices

Design System Foundations

What's in a Design System

Atomic Design Methodology

Atoms → Molecules → Organisms → Templates → Pages

Atoms:       Button, Input, Icon, Label
Molecules:   Form Field (Label + Input + Error)
Organisms:   Login Form (Fields + Button + Links)
Templates:   Auth Page Layout
Pages:       Login Page (Template + Real Content)

Design Tokens

Token Architecture

├── Global Tokens (Primitives)
│   ├── colors.blue.500: "#3B82F6"
│   ├── spacing.4: "16px"
│   └── font.size.base: "16px"
│
├── Semantic Tokens (Aliases)
│   ├── color.text.primary: colors.gray.900
│   ├── color.background.surface: colors.white
│   └── spacing.component.padding: spacing.4
│
└── Component Tokens (Specific)
    ├── button.background.default: color.primary.main
    ├── button.padding.horizontal: spacing.4
    └── card.border.radius: radius.medium

Token Implementation (.NET/​CSS)

// Token generation for .NET projects
public class DesignTokens
{
    public static class Colors
    {
        public static class Primary
        {
            public const string Main = "#3B82F6";
            public const string Light = "#60A5FA";
            public const string Dark = "#1D4ED8";
            public const string Contrast = "#FFFFFF";
        }

        public static class Semantic
        {
            public const string TextPrimary = "#111827";
            public const string TextSecondary = "#6B7280";
            public const string BackgroundSurface = "#FFFFFF";
            public const string BackgroundPage = "#F3F4F6";
            public const string BorderDefault = "#E5E7EB";
        }

        public static class Status
        {
            public const string Success = "#10B981";
            public const string Warning = "#F59E0B";
            public const string Error = "#EF4444";
            public const string Info = "#3B82F6";
        }
    }

    public static class Spacing
    {
        public const string Xs = "4px";
        public const string Sm = "8px";
        public const string Md = "16px";
        public const string Lg = "24px";
        public const string Xl = "32px";
        public const string Xxl = "48px";
    }

    public static class Typography
    {
        public static class FontSize
        {
            public const string Xs = "12px";
            public const string Sm = "14px";
            public const string Base = "16px";
            public const string Lg = "18px";
            public const string Xl = "20px";
            public const string Xxl = "24px";
            public const string Xxxl = "30px";
        }

        public static class FontWeight
        {
            public const string Normal = "400";
            public const string Medium = "500";
            public const string Semibold = "600";
            public const string Bold = "700";
        }

        public static class LineHeight
        {
            public const string Tight = "1.25";
            public const string Normal = "1.5";
            public const string Relaxed = "1.75";
        }
    }

    public static class Radius
    {
        public const string None = "0";
        public const string Sm = "2px";
        public const string Default = "4px";
        public const string Md = "6px";
        public const string Lg = "8px";
        public const string Xl = "12px";
        public const string Full = "9999px";
    }

    public static class Shadow
    {
        public const string Sm = "0 1px 2px 0 rgb(0 0 0 / 0.05)";
        public const string Default = "0 1px 3px 0 rgb(0 0 0 / 0.1)";
        public const string Md = "0 4px 6px -1px rgb(0 0 0 / 0.1)";
        public const string Lg = "0 10px 15px -3px rgb(0 0 0 / 0.1)";
    }
}

/​* CSS Custom Properties from tokens */
:root {
    /​* Colors - Primitives */
    --color-blue-50: #EFF6FF;
    --color-blue-500: #3B82F6;
    --color-blue-600: #2563EB;
    --color-blue-700: #1D4ED8;

    /​* Colors - Semantic */
    --color-primary-main: var(--color-blue-500);
    --color-primary-hover: var(--color-blue-600);
    --color-text-primary: var(--color-gray-900);
    --color-background-surface: var(--color-white);

    /​* Spacing */
    --spacing-1: 4px;
    --spacing-2: 8px;
    --spacing-4: 16px;
    --spacing-6: 24px;
    --spacing-8: 32px;

    /​* Typography */
    --font-size-sm: 14px;
    --font-size-base: 16px;
    --font-size-lg: 18px;
    --font-weight-medium: 500;
    --font-weight-bold: 700;
    --line-height-normal: 1.5;

    /​* Component Tokens */
    --button-padding-x: var(--spacing-4);
    --button-padding-y: var(--spacing-2);
    --button-border-radius: var(--radius-md);
    --card-padding: var(--spacing-4);
    --input-height: 40px;
}

Component Documentation

Component Specification Template

# Button Component

## Overview
Primary action trigger for user interactions.

## Anatomy
```

┌─────────────────────────────────────┐
│  [Icon]  Label Text  [Icon]         │
│                                     │
│  ← padding-x →     ← padding-x →    │
└─────────────────────────────────────┘

```

## Variants

| Variant | Use Case |
|---------|----------|
| Primary | Main actions, CTAs |
| Secondary | Alternative actions |
| Tertiary | Low-emphasis actions |
| Destructive | Dangerous/​irreversible actions |

## States
- Default
- Hover
- Active/​Pressed
- Focus
- Disabled
- Loading

## Sizes
| Size | Height | Font Size | Icon Size |
|------|--------|-----------|-----------|
| Small | 32px | 14px | 16px |
| Medium | 40px | 16px | 20px |
| Large | 48px | 18px | 24px |

## Props/​API

| Prop | Type | Default | Description |
|------|------|---------|-------------|
| variant | enum | primary | Visual style |
| size | enum | medium | Button size |
| disabled | boolean | false | Disabled state |
| loading | boolean | false | Loading state |
| iconLeft | ReactNode | - | Left icon |
| iconRight | ReactNode | - | Right icon |
| fullWidth | boolean | false | Full container width |

## Accessibility
- Use `<button>` element for actions
- Ensure visible focus state
- Minimum touch target: 44x44px
- Provide aria-label if icon-only
- Use aria-busy for loading state

## Do's and Don'ts

### Do
✓ Use verb-based labels ("Save", "Submit")
✓ Limit to one primary button per view
✓ Maintain sufficient contrast

### Don't
✗ Use vague labels ("Click here")
✗ Disable without explanation
✗ Use for navigation (use Link)

## Examples

### Basic Usage
```razor
<Button variant="primary">Save Changes</​Button>
```

### With Icons

```razor
<Button variant="secondary" iconLeft="@Icons.Plus">
    Add Item
</​Button>
```

### Loading State

```razor
<Button loading="@isSubmitting" disabled="@isSubmitting">
    @(isSubmitting ? "Saving..." : "Save")
</​Button>
```

## Related Components

- ButtonGroup - Grouping related buttons
- IconButton - Icon-only buttons
- Link - For navigation

Blazor Component Implementation

@namespace DesignSystem.Components

<button
    type="@Type"
    class="@ComputedClass"
    disabled="@(Disabled || Loading)"
    aria-busy="@Loading.ToString().ToLower()"
    @onclick="HandleClick"
    @attributes="AdditionalAttributes">

    @if (Loading)
    {
        <span class="btn-spinner" aria-hidden="true"></​span>
        <span class="visually-hidden">Loading</​span>
    }

    @if (IconLeft is not null && !Loading)
    {
        <span class="btn-icon btn-icon-left" aria-hidden="true">
            @IconLeft
        </​span>
    }

    <span class="btn-label">@ChildContent</​span>

    @if (IconRight is not null)
    {
        <span class="btn-icon btn-icon-right" aria-hidden="true">
            @IconRight
        </​span>
    }
</​button>

@code {
    [Parameter] public RenderFragment? ChildContent { get; set; }
    [Parameter] public ButtonVariant Variant { get; set; } = ButtonVariant.Primary;
    [Parameter] public ButtonSize Size { get; set; } = ButtonSize.Medium;
    [Parameter] public bool Disabled { get; set; }
    [Parameter] public bool Loading { get; set; }
    [Parameter] public bool FullWidth { get; set; }
    [Parameter] public RenderFragment? IconLeft { get; set; }
    [Parameter] public RenderFragment? IconRight { get; set; }
    [Parameter] public string Type { get; set; } = "button";
    [Parameter] public EventCallback<MouseEventArgs> OnClick { get; set; }
    [Parameter(CaptureUnmatchedValues = true)]
    public Dictionary<string, object>? AdditionalAttributes { get; set; }

    private string ComputedClass => new CssBuilder("btn")
        .AddClass($"btn-{Variant.ToString().ToLower()}")
        .AddClass($"btn-{Size.ToString().ToLower()}")
        .AddClass("btn-full-width", FullWidth)
        .AddClass("btn-loading", Loading)
        .AddClass("btn-disabled", Disabled)
        .Build();

    private async Task HandleClick(MouseEventArgs args)
    {
        if (!Disabled && !Loading)
        {
            await OnClick.InvokeAsync(args);
        }
    }
}

Design System Maturity Model

Maturity Levels

Maturity Assessment

public class DesignSystemMaturity
{
    public record MaturityScore(
        int Foundations,      // Tokens, primitives
        int Components,       // Component coverage
        int Documentation,    // Guidelines, examples
        int Tooling,          // Dev tools, testing
        int Governance,       // Process, contribution
        int Adoption          // Team usage
    )
    {
        public decimal OverallScore => (Foundations + Components + Documentation +
            Tooling + Governance + Adoption) / 6m;

        public MaturityLevel Level => OverallScore switch
        {
            >= 4.5m => MaturityLevel.Evolved,
            >= 3.5m => MaturityLevel.Integrated,
            >= 2.5m => MaturityLevel.Documented,
            >= 1.5m => MaturityLevel.Foundation,
            _ => MaturityLevel.Inconsistent
        };
    }

    public enum MaturityLevel
    {
        Inconsistent = 1,
        Foundation = 2,
        Documented = 3,
        Integrated = 4,
        Evolved = 5
    }
}

Versioning Strategy

Semantic Versioning for Design Systems

MAJOR.MINOR.PATCH

MAJOR: Breaking changes (renamed tokens, removed components)
MINOR: New features (new components, new variants)
PATCH: Bug fixes (visual fixes, docs updates)

Change Categories

Changelog Template

# Changelog

## [2.0.0] - 2025-01-15

### ⚠️ Breaking Changes
- **tokens**: Renamed `color-primary-*` to `color-brand-*`
- **Button**: Removed `type` prop, use `variant` instead

### 🚀 Added
- **DatePicker**: New date picker component
- **Button**: Added `ghost` variant
- **tokens**: Added dark mode tokens

### 🔧 Changed
- **Card**: Updated padding to use new spacing tokens
- **Input**: Improved focus ring visibility

### 🐛 Fixed
- **Modal**: Fixed focus trap for keyboard navigation
- **Select**: Fixed dropdown positioning in scrollable containers

### 📚 Documentation
- Added migration guide from v1 to v2
- New accessibility guidelines section

### ⚠️ Deprecated
- **Button**: `primary` variant renamed to `brand` (removal in v3)

Governance Model

Contribution Workflow

1. Proposal → 2. Review → 3. Design → 4. Build → 5. Document → 6. Release

Proposal:    Submit RFC with use case and requirements
Review:      Design system team evaluates fit
Design:      Create specs, get design approval
Build:       Implement with tests
Document:    Write guidelines, examples
Release:     Version, publish, communicate

RFC Template

# RFC: [Component/​Feature Name]

## Summary
Brief description of the proposed change.

## Motivation
Why is this needed? What problem does it solve?

## Use Cases
1. [Use case 1]
2. [Use case 2]

## Proposed Solution
### Design
[Screenshots, Figma links]

### API
[Props, tokens, usage examples]

### Accessibility
[WCAG considerations]

## Alternatives Considered
[Other approaches and why they were rejected]

## Open Questions
[Unresolved decisions]

## Adoption Strategy
[How will teams migrate/​adopt]

Decision Log

public class DesignDecision
{
    public required string Id { get; init; }
    public required string Title { get; init; }
    public required DateOnly Date { get; init; }
    public required string Context { get; init; }
    public required string Decision { get; init; }
    public required string Rationale { get; init; }
    public required List<string> Alternatives { get; init; }
    public required DecisionStatus Status { get; init; }
    public List<string> Supersedes { get; init; } = [];
    public string? SupersededBy { get; init; }
}

public enum DecisionStatus
{
    Proposed,
    Accepted,
    Superseded,
    Deprecated
}

Design-to-Code Workflow

Figma to Code Pipeline

Figma Design
    ↓
Token Export (Figma Tokens plugin)
    ↓
Token Transformation (Style Dictionary)
    ↓
Generated CSS/​Code
    ↓
Component Implementation
    ↓
Storybook Stories
    ↓
Visual Regression Tests
    ↓
Published Package

Token Transformation Config

// style-dictionary.config.json
{
  "source": ["tokens/​**/​*.json"],
  "platforms": {
    "css": {
      "transformGroup": "css",
      "buildPath": "dist/​css/",
      "files": [{
        "destination": "tokens.css",
        "format": "css/​variables"
      }]
    },
    "scss": {
      "transformGroup": "scss",
      "buildPath": "dist/​scss/",
      "files": [{
        "destination": "_tokens.scss",
        "format": "scss/​variables"
      }]
    },
    "csharp": {
      "transformGroup": "csharp",
      "buildPath": "dist/​csharp/",
      "files": [{
        "destination": "DesignTokens.cs",
        "format": "csharp/​class"
      }]
    }
  }
}

Adoption Metrics

Tracking Adoption

public class AdoptionMetrics
{
    public required decimal ComponentCoverage { get; init; }
    public required int TeamsAdopted { get; init; }
    public required int TotalTeams { get; init; }
    public required int ContributionsPastQuarter { get; init; }
    public required int OpenIssues { get; init; }
    public required decimal ConsistencyScore { get; init; }

    public decimal AdoptionRate => TeamsAdopted / (decimal)TotalTeams * 100;
}

Checklist: Design System Planning

Strategy

• Goals and success metrics defined
• Target audience identified
• Scope determined (which products)
• Team and governance established
• Tech stack decided

Foundation

• Design tokens defined
• Color system established
• Typography scale set
• Spacing system created
• Grid system defined

Components

• Component audit completed
• Priority components identified
• Component specs created
• Accessibility requirements defined
• Implementation approach decided

Documentation

• Documentation platform chosen
• Component documentation template
• Usage guidelines written
• Example code provided
• Contribution guide created

Tooling

• Design tool integration (Figma)
• Storybook or equivalent
• Visual regression testing
• Linting rules
• CI/​CD pipeline

Governance

• Versioning strategy
• Release process
• RFC/​proposal process
• Support model
• Feedback channels

Related Skills

• accessibility-planning - Accessible components
• prototype-strategy - Prototyping with design system
• heuristic-evaluation - Evaluating consistency
• information-architecture - Navigation patterns