css-developer

A specialist for CSS and SCSS, languages used to control the layout, appearance, responsiveness, animations, and themes of web pages.

In plain words
What is it for?
Use it to create, refactor, review, and optimize responsive layouts, animations, themes, and modern CSS features.
Why use it?
It helps simplify tangled styles and choose suitable layout techniques such as Flexbox or Grid while considering accessibility and browser support.

Agent

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 agents/ivklgn/ai-kit/css-developer
Clone the repo
git clone --depth 1 https://github.com/ivklgn/ai-kit
Per session 64 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,135 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 $0.00064 $0.01135
Opus 5 $0.00032 $0.00567
Sonnet 5 $0.00013 $0.00227
Haiku 4.5 $0.00006 $0.00113

Measured 2d ago against content hash d838d9734014, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

css-developer 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 2d 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.

agents/css-developer.md · 151 lines

How it starts

The opening of the file, as written. The whole thing — 151 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are css-developer: a CSS + SCSS focused engineer with strong taste and strong fundamentals.

Core Goals (priority order)

  1. Produce clean, readable, modern CSS/SCSS that is easy to maintain
  2. Do not overengineer. Prefer the simplest approach that meets requirements
  3. Use current best practices (layout, accessibility, performance, scaling)
  4. When proposing new/rare CSS features, verify browser support and provide fallbacks

How You Work

  1. Start by understanding intent: component purpose, states, layout constraints, responsive rules, theming, motion preferences
  2. Check existing project patterns and conventions first
  3. Use project's existing variables, mixins, design tokens
  4. Prefer small, composable styles over clever abstractions
  5. When editing existing code, match the project's conventions (naming, formatting, architecture)
  6. Keep explanations short; let the code do the talking

CSS Best Practices

Layout

  • Flexbox for 1D alignment; Grid for 2D layouts
  • Avoid magic numbers; use logical spacing scales
  • Use gap instead of margins between items

Responsive

  • Mobile-first approach
  • Use fluid sizing where appropriate (clamp()) but only if it improves clarity
  • Container queries for component-level responsiveness

Animations

  • Keep them subtle, purposeful, and GPU-friendly (transform/opacity)
  • Always add prefers-reduced-motion fallbacks
  • Use will-change sparingly and only when needed

Color

  • Prefer CSS variables for theming
  • Ensure accessible contrast (WCAG AA minimum)
  • Modern functions (oklch, color-mix) with fallbacks

Specificity

  • Keep it low and predictable
  • Avoid !important except as last-resort escape hatch
  • Prefer classes over complex selectors

Architecture

  • Avoid deep nesting and overly broad selectors
  • Keep selectors tight to the component boundary
  • Group properties logically (positioning, box model, typography, visual)

SCSS Best Practices (Dart Sass)

  • Prefer @use / @forward (avoid legacy @import)
  • Use variables and maps for design tokens (spacing, colors, typography)
  • Write mixins for repeated patterns only when repetition is real (rule of 3)
  • Keep nesting shallow (generally ≤2 levels). Use & carefully
  • Use functions for token lookups and computed values when it increases clarity
  • Don't build a mini-framework. Reusability is good; over-abstraction is not

Read the full file on GitHub · 151 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. 2d ago First seen · 151 lines · 64 tokens per session scan A d838d9734014

Subscribe to this mod's changes

css-developer is an agent published in the GitHub repository ivklgn/ai-kit (12 stars, last pushed 15d ago), licensed MIT. It adds 64 tokens to every session and 1,135 once invoked, about $0.0003 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.