styling

Project rules for styling a Ruby on Rails application with Tailwind CSS, a system of small reusable styling classes.

In plain words
What is it for?
Use them when adding or reviewing page styles, configuring Tailwind in Rails, choosing responsive utility classes, or preparing styles for production.
Why use it?
They help keep styles consistent, responsive, and close to the HTML while avoiding unnecessary custom CSS and complicated build setup.

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/levifig/rails-instructions/styling
Clone the repo
git clone --depth 1 https://github.com/levifig/rails-instructions

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 1,004 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 $0.01004
Opus 5 $0.00000 $0.00502
Sonnet 5 $0.00000 $0.00201
Haiku 4.5 $0.00000 $0.00100

Measured yesterday against content hash 67fa2ff51fbf, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

styling 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/rails/styling.mdc · 185 lines

How it starts

The opening of the file, as written. The whole thing — 185 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Rails Styling with TailwindCSS

Core Philosophy

  • Use utility-first CSS for rapid development
  • Avoid writing custom CSS when utilities exist
  • Keep styling consistent across the application
  • Design mobile-first, enhance for desktop
  • Let TailwindCSS handle the complexity

TailwindCSS Principles

  • Compose styles using utility classes
  • Avoid premature abstraction into components
  • Use consistent spacing and sizing scales
  • Leverage TailwindCSS's design system
  • Keep HTML as the source of truth for styling

Configuration Strategy

  • Extend default theme rather than replacing it
  • Define custom colors sparingly
  • Use CSS variables for dynamic theming
  • Configure content paths correctly
  • Keep configuration minimal

Rails Integration

  • Use Tailwind's standalone CLI approach
  • Configure asset pipeline integration properly
  • Set up proper purging for production
  • Use Rails helpers with Tailwind classes
  • Keep build process simple

Utility-First Approach

  • Start with utilities before extracting components
  • Use modifier classes for responsive design
  • Apply state modifiers directly in HTML
  • Leverage arbitrary values when needed
  • Keep utility usage consistent

Component Patterns

  • Extract components only when truly reusable
  • Use @apply sparingly and deliberately
  • Keep extracted components simple
  • Document component patterns clearly
  • Prefer composition over complex components

Responsive Design

  • Design mobile-first always
  • Use breakpoint prefixes consistently
  • Test at all breakpoint sizes
  • Consider touch targets on mobile
  • Optimize for common device sizes

Color Management

  • Use Tailwind's color palette
  • Define semantic color names
  • Maintain consistent color usage
  • Support dark mode properly
  • Test color accessibility

Typography System

  • Use Tailwind's typography scale
  • Keep font sizes consistent
  • Implement proper line heights
  • Use appropriate font weights
  • Consider readability always

Spacing Guidelines

  • Use Tailwind's spacing scale exclusively
  • Keep spacing consistent throughout
  • Apply spacing systematically
  • Use negative margins carefully
  • Document spacing decisions

Read the full file on GitHub · 185 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. yesterday First seen · 185 lines · 0 tokens per session scan A 67fa2ff51fbf

Subscribe to this mod's changes

styling is a cursor rule published in the GitHub repository levifig/rails-instructions (54 stars, last pushed 1y ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,004 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.