css-architecture

css-architecture is a skill for Claude Code from eugenelim/agent-ready-repo. It costs 74 tokens per session (2,697 once invoked), scanned A, original, Apache-2.0.

A CSS organization skill for large or growing codebases. It uses cascade layers, scoping, and limits on selector specificity to make it clearer which style wins.

In plain words
What is it for?
Use it when designing CSS structure for a new project or refactoring styles with specificity conflicts and unpredictable cascades.
Why use it?
It reduces conflicting CSS rules, unexpected visual changes, and the fear of deleting a rule because its effects are unclear.

Skill for Claude Code

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

Part of the frontend-engineering plugin — 9 skills, 1 agent shipped together

Good fit Use it when designing CSS structure for a new project or refactoring styles with specificity conflicts and unpredictable cascades.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/eugenelim/agent-ready-repo/css-architecture
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 eugenelim/agent-ready-repo --skill css-architecture
Clone the repo
git clone --depth 1 https://github.com/eugenelim/agent-ready-repo

Made for: Claude Code.

Or install frontend-engineering, the plugin that ships this one along with the rest of its 9 skills, 1 agent.

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 css-architecture

README.md
[![agentmods](https://agentmods.dev/badge/skills/eugenelim/agent-ready-repo/css-architecture/github.svg)](https://agentmods.dev/skills/eugenelim/agent-ready-repo/css-architecture)
Your own site
<a href="https://agentmods.dev/skills/eugenelim/agent-ready-repo/css-architecture"><img src="https://agentmods.dev/badge/skills/eugenelim/agent-ready-repo/css-architecture/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 css-architecture

Your own site · 80×15
<a href="https://agentmods.dev/skills/eugenelim/agent-ready-repo/css-architecture"><img src="https://agentmods.dev/badge/skills/eugenelim/agent-ready-repo/css-architecture.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 74 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,697 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 2 findings, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Prompt Injection · line 248
    Hidden instructions were detected in comments or invisible text. These could contain malicious directives. Manual review is recommended.
    Fix: Audit all comments and invisible characters. Remove any instructions that direct the agent to perform unauthorized actions. Use plain, reviewable content.
  • medium Prompt Injection · line 48
    Subtle instructions detected that may alter agent decision-making or introduce hidden biases.
    Fix: Review content for implicit steering or bias. Ensure instructions are explicit and align with the skill's stated purpose.
How audits are shown
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 $0.00074 $0.02697
Opus 5 $0.00037 $0.01349
Sonnet 5 $0.00015 $0.00539
Haiku 4.5 $0.00007 $0.00270

Measured 5d ago against content hash 1cd449a26cb0, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

css-architecture 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 5d 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.

packs/frontend-engineering/.apm/skills/css-architecture/SKILL.md · 266 lines

How it starts

The opening of the file, as written. The whole thing — 266 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Skill: css-architecture

Load this skill when setting up CSS architecture for a new codebase, or auditing and refactoring CSS in an existing one where specificity conflicts, hard-to-predict cascade behavior, or unsafe deletion are active problems. Do not load it for routine component styling on a codebase that already has a working architecture. Load css-architecture when:

  • Starting a new project and deciding the CSS organization strategy
  • A codebase has accumulated specificity conflicts that produce unpredictable cascades
  • Engineers cannot safely delete a CSS rule because they don't know what will break
  • The codebase has grown beyond one developer and CSS changes produce unexpected regressions

Cascade layers

@layer (Cascade Layers) is Baseline Widely Available as of 2022. It makes the cascade explicit and controllable: a rule in a higher layer always wins over a rule in a lower layer, regardless of specificity.

Canonical layer order:

/* Declare all layers upfront — this is the only place layer order is defined */
@layer reset, base, theme, components, utilities, overrides;
Layer Contents Notes
reset Browser default reset (e.g., box-sizing, margins) No project-specific styles
base HTML element defaults (body font, heading scale, link style) Unclassed element selectors only
theme Design token custom properties (:root {} token block) No component styles
components Component class selectors (.btn, .card, .modal) The main application CSS lives here
utilities Single-purpose utility classes (hidden, sr-only, spacing helpers) High-frequency reuse; should have low specificity
overrides Escape hatch for third-party library overrides, print styles Rarely used; document every rule added here

Why ordering is the invariant: a rule in utilities always beats a rule in components, regardless of how specific the component rule is. This means utilities are reliable (you can always use a utility to override a component style), but components cannot override utilities. The layer order must be declared once at the top of the main stylesheet — never redeclare it in component files.

Read the full file on GitHub · 266 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 5d ago Changed · +35 tokens per session 1cd449a26cb0
  2. 6d ago First seen · 266 lines · 39 tokens per session scan A 8f5cea415caa

Subscribe to this mod's changes

css-architecture is a skill published in the GitHub repository eugenelim/agent-ready-repo (20 stars, last pushed today), licensed Apache-2.0. It adds 74 tokens to every session and 2,697 once invoked, about $0.0004 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 2026-09-03.

Related

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