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CSS @property Registration Guide

Guides the agent to register CSS custom properties with @property for animation and typed tokens

Source Download skill
Repository
thedaviddias/Front-End-Checklist
Stars
74,632
Licence
MIT
Files
2 files

What it does

This skill teaches the agent a specific CSS technique: registering custom properties (CSS variables) with the @property rule so browsers can animate them, for example smooth gradient transitions, and validate their types, such as color or length. When you ask for help with a CSS animation or design token setup, the agent will check whether custom properties used in transitions are registered, add missing @property rules with a syntax, initial-value and inherits setting, and explain the results. It does not run code itself; it works by guiding the agent's written CSS suggestions and reviews.

Great for

  • Front-end developers building animated gradients or transitions that use CSS variables
  • Teams creating typed design token systems who want invalid token values to surface errors
  • Developers reviewing existing CSS for unregistered custom properties used in animations

Skip it if

  • Projects that must support older browsers, since @property is not available everywhere and the skill does not cover fallbacks in its file (the rule text itself is focused on modern usage)
  • Simple styling tasks that do not involve animating or typing custom properties, where the skill adds unnecessary complexity
  • Non-CSS work: the skill has no relevance to JavaScript, backend or document tasks

Try asking

  • “Make my gradient background animate smoothly on hover using a CSS custom property”
  • “Review this stylesheet and flag any custom properties used in transitions that are not registered with @property”
  • “Add @property registrations with proper syntax and initial-value for these design tokens”
  • “Explain why my CSS variable transition jumps instead of animating”
Step-by-step guide: how to use CSS @property Registration GuideInstall, first run, examples, tips and FAQs

Install in 3 steps

  1. 1

    Download the skill

    The ZIP contains the 2 original files, the MIT licence and an attribution note.

    css-at-property.zip
  2. 2

    Add it to your agent

    Claude Code (all projects)

    mkdir -p ~/.claude/skills && unzip css-at-property.zip -d ~/.claude/skills/

    Claude Code / Agent SDK (this project only)

    mkdir -p .claude/skills && unzip css-at-property.zip -d .claude/skills/

    Claude apps (web/desktop): Settings → Capabilities → Skills → Upload skill, and choose the ZIP.

  3. 3

    Ask for the task

    No special command needed — the agent reads the skill's description and loads it when your request matches. Try one of the prompts above.

Get better results

  • Give the agent your actual CSS so it can check transitions and animations against registered properties
  • Specify which syntax you need (color, length, number) so the registrations match your token types
  • Ask for the reference examples in references/rule.md when you need framework-specific code

What's inside

  • references/rule.md
  • SKILL.md

Redistributed unmodified from thedaviddias/Front-End-Checklist under the MIT licence. The assessment was drafted with AI from the skill's files on 2026-10-29. Skills can instruct your agent to run code — read SKILL.md and any scripts before installing.