dark-mode

dark-mode is a skill for Claude Code from dylantarre/design-system-skills. It costs 43 tokens per session (4,081 once invoked), scanned A, original, MIT.

Instructions for adding light and dark appearance modes to an interface using shared colour settings and system-preference detection. A theme toggle lets users switch between these modes.

In plain words
What is it for?
Use it to add dark mode, light/dark switching, automatic detection of a user's device preference, or theme-aware colours to an existing project.
Why use it?
It replaces scattered hardcoded colours with organised settings, making both themes easier to maintain and keeping the interface readable across modes.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the design-system-skills plugin — 29 skills shipped together

Good fit Use it to add dark mode, light/dark switching, automatic detection of a user's device preference, or theme-aware colours to an existing project.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/dylantarre/design-system-skills/dark-mode
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add dylantarre/design-system-skills --skill dark-mode
Clone the repo
git clone --depth 1 https://github.com/dylantarre/design-system-skills

Made for: Claude Code.

Or install design-system-skills, the plugin that ships this one along with the rest of its 29 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for dark-mode

README.md
[![agentmods](https://agentmods.dev/badge/skills/dylantarre/design-system-skills/dark-mode/github.svg)](https://agentmods.dev/skills/dylantarre/design-system-skills/dark-mode)
Your own site
<a href="https://agentmods.dev/skills/dylantarre/design-system-skills/dark-mode"><img src="https://agentmods.dev/badge/skills/dylantarre/design-system-skills/dark-mode/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for dark-mode

Your own site · 80×15
<a href="https://agentmods.dev/skills/dylantarre/design-system-skills/dark-mode"><img src="https://agentmods.dev/badge/skills/dylantarre/design-system-skills/dark-mode.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 43 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,081 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00043 $0.04081
Opus 5 $0.00022 $0.02041
Sonnet 5 $0.00009 $0.00816
Haiku 4.5 $0.00004 $0.00408

Measured 12d ago against content hash 56d6cb6ae5b2, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

dark-mode scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 12d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/patterns/dark-mode/SKILL.md · 566 lines

How it starts

The opening of the file, as written. The whole thing — 566 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Dark Mode Implementation

Overview

Implement robust dark mode using semantic color tokens, CSS custom properties, and system preference detection. Creates a theme system that's maintainable, accessible, and works across frameworks.

When to Use

  • Adding dark mode to an existing project
  • Setting up a theme system from scratch
  • Converting hardcoded colors to semantic tokens
  • Implementing system preference detection
  • Building a theme toggle component

Quick Reference: Theme Architecture

Layer Purpose Example
Primitive tokens Raw color values --color-blue-500: #3b82f6
Semantic tokens Purpose-based aliases --color-primary: var(--color-blue-500)
Theme tokens Mode-specific values --color-bg: var(--color-gray-50) in light
Component tokens Component-specific --button-bg: var(--color-primary)

The Process

  1. Audit existing colors: Find all color usage in codebase
  2. Define primitive palette: Use color-scale skill if needed
  3. Create semantic tokens: Map primitives to purposes
  4. Define theme tokens: Light and dark values
  5. Choose switching mechanism: CSS classes, data attributes, or media query
  6. Add system detection: prefers-color-scheme
  7. Implement persistence: localStorage or cookies
  8. Handle edge cases: Images, shadows, third-party components

Implementation Checklist

Copy this checklist and track progress:

Dark Mode Implementation:
- [ ] Audit colors in codebase (grep for hex, rgb, hsl, color names)
- [ ] Create semantic token layer (bg, text, border, surface, interactive, status)
- [ ] Define light and dark theme values for all semantic tokens
- [ ] Implement switching mechanism (data-theme attribute recommended)
- [ ] Add system preference detection (prefers-color-scheme)
- [ ] Add inline script in <head> to prevent flash of wrong theme
- [ ] Build toggle component with localStorage persistence
- [ ] Handle edge cases (images, shadows, third-party components, form inputs)
- [ ] Test contrast ratios meet WCAG AA in both themes

Read the full file on GitHub · 566 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 12d ago First seen · 566 lines · 43 tokens per session scan A 56d6cb6ae5b2

Subscribe to this mod's changes

dark-mode is a skill published in the GitHub repository dylantarre/design-system-skills (43 stars, last pushed 8mo ago), licensed MIT. It adds 43 tokens to every session and 4,081 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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