Design systems have become essential in modern digital product development, helping teams deliver consistent, efficient, and accessible experiences at scale. But while the term “design system” is widely used, its true power lies in understanding the core building blocks that make it work.
At its heart, a design system is built from three fundamental parts: design tokens, UI components, and guidelines/documentation. These elements work together to create a single source of truth that empowers teams — from designers to developers to content creators — to build unified digital products faster and better.
In this post, we’ll explore these three pillars in detail, looking at what they are, why they matter, and how to implement and maintain them effectively.
1. Design Tokens: The Foundation of Visual Consistency
Imagine a digital product with multiple teams working on different features. Without a shared language of design, it’s easy for colours, typography, spacing, and other visual elements to drift apart, leading to inconsistent experiences that confuse users and complicate maintenance.
Design tokens solve this problem by acting as the single source of truth for all visual styles.
What Exactly Are Design Tokens?
Design tokens are the atomic pieces of a design system — essentially, they’re variables that store design decisions like colour values, font sizes, spacing units, and more. They exist in a format that can be shared and consumed across different platforms, design tools, and development environments.
Here are some examples of common design tokens:
- Colours: Primary brand colours, background colours, text colours, semantic colours for success/error/warning
- Typography: Font sizes, line heights, font weights, font families
- Spacing: Margins and paddings at various scales (e.g., 4px, 8px, 16px)
- Borders: Border widths, radius, and styles
- Shadow/Elevation: Drop shadows and layering cues
- Animation: Timing durations and easing functions
Why Use Design Tokens?
- Consistency Across Platforms
Design tokens ensure that the same values are used everywhere — from web CSS to native mobile apps. This consistency means users experience a unified brand no matter where they interact with your product. - Easy Updates
If you need to change a colour or adjust spacing, you update the token once, and that change ripples across every instance where it’s used — no tedious hunting through code or design files. - Scalability
As your product grows or you add new brands/themes, tokens enable easy customization without rebuilding everything.
How Design Tokens Are Managed
Managing tokens manually can get complex as the number grows. That’s where tools like Style Dictionary or plugins like Tokens Studio for Figma come in. These tools help you:
- Define tokens in a central repository (JSON, YAML, etc.)
- Export tokens into platform-specific formats (CSS variables, SCSS, JSON, XML)
- Keep design and development in sync by connecting design tools with codebases
Practical Example: Colour Tokens
Instead of hardcoding colours, use tokens like:
cssCopyEdit--color-primary: #0055A5;
--color-background: #FFFFFF;
--color-error: #D93025;
If the brand colour changes, just update --color-primary once.
2. UI Components: Reusable Building Blocks of Your Interface
If design tokens are the atoms, UI components are the molecules that make up your product’s interface. They are self-contained, reusable pieces of UI designed to work consistently wherever they’re used.
What Are UI Components?
Components include everything from buttons and input fields to more complex structures like modals, tabs, and navigation menus.
They’re typically developed and maintained as:
- Code components in frameworks like React, Vue, or Angular
- Design files in tools like Figma, with variants and states for different interactions
- Documentation covering usage, accessibility, and code examples
Why Components Matter
- Reduce Duplication
Instead of building the same button or form multiple times, teams reuse components, reducing bugs and inconsistencies. - Ensure Accessibility
When components are built with accessibility baked in, every product built on the system benefits without extra work. - Speed Up Development
Developers spend less time coding UI from scratch, focusing instead on business logic and innovation. - Unify Design and Code
With clear design specs and coded components, designers and developers can collaborate effectively.
Examples of Common Components
- Buttons — primary, secondary, disabled states
- Form Fields — text inputs, checkboxes, radios
- Modals — alerts, confirmations
- Cards — content containers with images and text
- Tabs and Accordions — content toggles
- Notifications/Alerts — success, error, info messages
Component Variants and States
Good component libraries include variants — versions tailored for different contexts (e.g., a large vs small button, or a form input with an error state). States cover user interactions like hover, focus, disabled, or active.
Having these predefined saves guesswork and helps deliver predictable, polished experiences.
Building and Maintaining Components
Building components is an iterative process:
- Design: Create detailed specs in design tools, covering layout, typography, colours, and interaction states.
- Develop: Implement components with clean, accessible code. Use CSS variables linked to tokens.
- Test: Verify usability and accessibility. Automate UI tests where possible.
- Document: Write clear usage guidelines and examples.
- Version: Use version control to manage updates and communicate breaking changes.
3. Guidelines and Documentation: Enabling Effective Use
Components and tokens alone aren’t enough — teams need clear rules and context to use them well. That’s where guidelines and documentation come in.
What Should Good Documentation Cover?
- When and How to Use Components
Explain the purpose of each component, appropriate contexts, and examples. - Accessibility Requirements
Detail keyboard behaviour, ARIA roles, and focus management best practices. - Content Guidelines
Provide tone of voice, writing style, and content formatting tips that complement the UI. - Design Rationale
Share why components or tokens are designed the way they are to build understanding and trust. - Contribution Process
Outline how team members can propose changes or add new components to the system. - Common Pitfalls
Show examples of misuse and how to avoid them.
Why Documentation Is Critical
Clear, accessible documentation empowers teams to:
- Use the design system independently
- Reduce back-and-forth questions
- Onboard new members faster
- Maintain design and development alignment
Documentation tools vary from static websites to integrated platforms like Storybook, Zeroheight, or Confluence — the key is making it discoverable and easy to update.
How Tokens, Components, and Guidelines Work Together
These three pillars are interdependent:
- Tokens set the visual language with consistent values.
- Components apply tokens to deliver functional, accessible UI elements.
- Guidelines ensure teams use tokens and components correctly, maintaining quality and coherence.
Together, they create a system that grows with your products and teams — reducing technical debt, improving user experience, and accelerating delivery.
Additional Considerations When Building Your Design System
Accessibility Must Be a Priority
Embed accessibility at every stage: tokens should include colour contrast considerations; components must be keyboard navigable; documentation must explain accessibility requirements.
Accessibility isn’t optional — it’s a foundation.
Collaboration Is Key
A design system is only successful when teams across disciplines contribute and adopt it. Encourage designers, developers, writers, and QA to participate in governance and feedback.
Start Small and Scale
You don’t have to build a comprehensive system overnight. Start with your most critical components and tokens, iterate based on feedback, and grow organically.
Keep Your System Evolving
Technology changes, brands evolve, and user needs shift. Your design system must be a living product with ongoing maintenance, updates, and improvements.
Tools That Support Design Tokens, Components, and Documentation
- Figma: Popular for designing components and managing tokens with plugins.
- Storybook: For developing and documenting UI components in code.
- Style Dictionary: For managing and exporting tokens across platforms.
- Zeroheight: Bridges design files with documentation for teams.
- GitHub/GitLab: Version control and collaboration.
Choose tools that fit your team’s workflow and support collaboration.
Design systems might seem complex at first glance. But once you understand their core building blocks — design tokens, components, and guidelines — they become tangible tools you can use to create better digital products.
They reduce repetitive work, increase consistency, improve accessibility, and align teams around shared goals.
Next time you work on a digital project, consider how these elements can streamline your processes and improve outcomes.