Theme System

Q: What is a Claude Code skill and how does the Theme System skill fit in?

A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. Theme System is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Engineering category. Learn more at https://claudskills.com/learn/what-is-skill-md/.

Category: Engineering · Sub-category: frontend · Last updated: 2026-05-21

The Lossless Group's theme and mode architecture — two-tier token system, three-mode contract (light/dark/vibrant), theme.css organization, and design system conventions. Use when setting up themes/modes for any Astro Knots site, debugging mode toggles, working with CSS tokens, or when the user mentions "vibrant mode", "two-tier tokens", "theme.css", or design system patterns.

Security AStatic scan found no risk patternsHow grading works ›

From the source SKILL.md

The Lossless Group's firm-wide conventions for theme architecture, visual modes, and design token systems.

What this skill does

Theme System is a community-contributed Claude Code skill in the frontend sub-category. It ships as a SKILL.md file that Claude Code auto-discovers under ~/.claude/skills/theme-system/ and loads when your prompt matches the skill's trigger.

When to invoke it: Use when setting up themes/modes for any Astro Knots site, debugging mode toggles, working with CSS tokens, or when the user mentions "vibrant mode", "two-tier tokens", "theme.css", or design system patterns.

Who uses this skill

The Theme System Claude Code skill is built for software engineers, backend developers, full-stack teams, and technical leads building and maintaining production systems. It's part of ClaudSkills (also referred to as Claude Skills or Claude Code Skills) — the open community-curated registry of 158,000+ SKILL.md files for Anthropic's Claude Code agent and the wider Claude ecosystem (Claude API, Claude Agent SDK).

How to install

Free

Manual install (2 steps)

mkdir -p ~/.claude/skills/theme-system
curl -L https://claudskills.com/skills/theme-system/SKILL.md \
  -o ~/.claude/skills/theme-system/SKILL.md

Or just download SKILL.md directly and drop it into ~/.claude/skills/theme-system/. Claude Code auto-discovers it on next session.

Skills live at ~/.claude/skills/theme-system/SKILL.md on macOS/Linux, or %USERPROFILE%\.claude\skills\theme-system\SKILL.md on Windows. See the full install guide for step-by-step instructions.

📱 Install from your phone or desktop Telegram

Open @claudskills_bot on Telegram, tap Open Desktop App, and the desktop app installs this skill for you. Or share the bot link with a colleague — they get the same one-tap install. Learn more →

Pro

One-click install via the desktop app

The ClaudSkills desktop app installs any skill directly into ~/.claude/skills/ with one click — no terminal required. Pro starts at $9/mo or $149 lifetime.

Pro

For the full experience including quality scoring and one-click install features for each skill — upgrade to Pro.

See pricing → Download desktop app

Frequently asked questions

How do I install the Theme System Claude Code skill?

Install via the ClaudSkills desktop app (one click) or copy SKILL.md from the source repository to ~/.claude/skills/theme-system/SKILL.md and restart Claude Code. Both flows are detailed at claudskills.com/install/.

What does the Theme System skill do?

Is this skill free to install?

Yes. ClaudSkills is an open registry — every skill keeps its source repository's license, and manual install via copy is free. ClaudSkills Pro ($9/mo, $79/yr, or $149 one-time) adds one-click install via the desktop app and a multi-signal Quality Score.

When should I use the Theme System skill?

Use Theme System when your Claude Code task falls under the Engineering category — specifically in the frontend area. Claude Code auto-discovers installed skills and invokes the right one based on the task description, so you can also ask Claude directly (e.g. "use Theme System" or describe the task and let Claude pick). Browse related skills at /category/engineering/.

What is a Claude Code skill and how does the Theme System skill fit in?

A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. Theme System is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Engineering category. Learn more at /learn/what-is-a-claude-skill/.

Attribution & license

Source: https://github.com/lossless-group/lossless-agent-skills/blob/HEAD/theme-system/SKILL.md
Author: lossless-group

Cite this skill

If you reference this skill in a blog post, paper, or documentation, you can cite it as:

APA

lossless-group. (2026). Theme System [Claude Code skill]. ClaudSkills. https://claudskills.com/skills/theme-system/

BibTeX

@misc{theme-system-2026,
  author    = {lossless-group},
  title     = {Theme System [Claude Code skill]},
  year      = {2026},
  publisher = {ClaudSkills},
  url       = {https://claudskills.com/skills/theme-system/}
}

Embed this skill

Promote, attribute, or link this skill from your own README, blog post, or documentation. All three snippets are free to use — no sign-up, no API key. More distribution surfaces →

Badge

[![ClaudSkills](https://claudskills.com/badge/theme-system.svg)](https://claudskills.com/skills/theme-system/?utm_source=badge&utm_medium=readme&utm_campaign=skill_badge)

Security scan

Grade A · scanned 2026-07-23 — free static scan against the OWASP Agentic Skills Top 10.

No risk patterns were found in any of the ten OWASP-aligned categories. How grading works ›

✓ Prompt injection
✓ Data exfiltration
✓ Supply chain
✓ Reverse shell
✓ Credentials
✓ Execution
✓ Filesystem
✓ Persistence
✓ Obfuscation
✓ Network

Show this grade on your repo (click to copy):

[![Security: A](https://img.shields.io/badge/Security-A-2e7d32)](https://claudskills.com/skills/theme-system/#security)

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Browse all Engineering skills → Top 100 skills

Part of ClaudSkills — the open registry for Claude Skills & Claude Code Skills. · What's New · Install guide · About · llms.txt

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