frontend-css

A set of project rules for writing CSS, including themes, responsive layouts, touch targets, hover behavior, and matching CSS selectors with JavaScript.

In plain words
What is it for?
Use it when changing themed components, mobile layouts, touch controls, hover-only UI, or renamed CSS classes and element IDs.
Why use it?
It helps keep styling consistent across light and dark themes, desktop and mobile screens, and interactive code.

Cursor rule for Cursor

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.

agentmods
npx agentmods add rules/tomasz-tomczyk/crit/frontend-css
Clone the repo
git clone --depth 1 https://github.com/tomasz-tomczyk/crit

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 321 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00000 $0.00321
Opus 5 $0.00000 $0.00161
Sonnet 5 $0.00000 $0.00064
Haiku 4.5 $0.00000 $0.00032

Measured yesterday against content hash 8d5a754d4974, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

frontend-css 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 yesterday.

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.

.cursor/rules/frontend-css.mdc · 21 lines

What it actually says

CSS Rules

Theming (Stylelint catches hardcoded colors; check-css-vars.sh catches undefined vars)

  • When adding themed elements, define color values in ALL 4 theme blocks in theme.css: :root (dark fallback), prefers-color-scheme: light, [data-theme="dark"], [data-theme="light"].

Responsive & Touch

  • Mobile layout rules go inside @media (max-width: 768px). Touch affordances go inside @media (pointer: coarse). Desktop-only hover interactions go inside @media (pointer: fine).
  • Hover-only interactive elements (.line-add, .diff-comment-btn) must be display: none by default and display: flex inside @media (pointer: fine). This prevents flash-on-tap on touch devices where .drag-endpoint briefly applies.
  • Touch targets must be ≥ 44×44px under @media (pointer: coarse) (WCAG 2.5.5).
  • Comment textarea and reply input must be font-size: 16px under mobile to suppress iOS Safari focus-zoom.

Selectors

  • After renaming a CSS class or DOM element ID, search for and remove ALL references to the old name in CSS AND JS.
  • Check that all CSS selectors referenced in JS (querySelector, classList.contains) match actual class names in CSS.
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. yesterday First seen · 21 lines · 0 tokens per session scan A 8d5a754d4974

Subscribe to this mod's changes

frontend-css is a cursor rule published in the GitHub repository tomasz-tomczyk/crit (979 stars, last pushed 3d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 321 tokens. 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.