TIL: Dark Mode Toggle Web Component by Google Chrome Labs

Today I learned about a custom web component from Google Chrome Labs that makes it easy to add dark mode functionality to websites.

March 15, 2021 · 2 min

Table of Contents

Web Components and Dark Mode
- Dark Mode Toggle Custom Element
Key Features
Dark Mode Best Practices
- Design Considerations
- Implementation Patterns
Key Takeaways

Web Components and Dark Mode

Dark Mode Toggle Custom Element

GitHub - GoogleChromeLabs/dark-mode-toggle
Custom HTML element for adding dark mode toggles to websites
Developed by Google Chrome Labs for easy dark mode implementation
Standards-based web component that works across frameworks

Key Features

Easy Integration

Custom Element: Use as simple HTML tag <dark-mode-toggle>
Framework Agnostic: Works with any framework or vanilla HTML
No Dependencies: Self-contained web component
Accessibility: Built with accessibility best practices

User Experience

Persistent Preference: Remembers user’s dark mode choice
System Integration: Respects OS-level dark mode preferences
Smooth Transitions: Provides smooth visual transitions
Customizable: Configurable appearance and behavior

Technical Implementation

CSS Custom Properties: Uses CSS variables for theming
Local Storage: Persists user preferences across sessions
Media Queries: Integrates with prefers-color-scheme
Progressive Enhancement: Works without JavaScript as fallback

Dark Mode Best Practices

Design Considerations

Color Contrast: Ensure sufficient contrast in both modes
Image Handling: Consider image visibility in dark themes
Brand Colors: Adapt brand colors for dark backgrounds
User Choice: Always allow user override of system preferences

Implementation Patterns

CSS Variables: Use custom properties for easy theme switching
Semantic Colors: Define colors by purpose, not appearance
Component Isolation: Ensure components work in both modes
Testing: Test thoroughly in both light and dark modes

Key Takeaways

User Experience: Dark mode is becoming an expected feature
Web Standards: Custom elements provide reusable, standards-based solutions
Accessibility: Consider user preferences and system settings
Developer Experience: Well-designed components simplify implementation
Progressive Enhancement: Build features that work with or without JavaScript

This component demonstrates how web standards and thoughtful design can make complex features (like theme switching) simple to implement while maintaining excellent user experience and accessibility.