Is the HTML CSS First skill free?

Yes. The skill itself is free from macdonst/html-css-first. SkillProof publishes the install command and an independent test verdict at no cost.

What is the HTML CSS First SkillProof Score?

9.2/10 — installs cleanly 5/5, triggers reliably 5/5, output vs. baseline 9/10, docs & honesty 4/5.

How do I install HTML CSS First?

Copy the install command from this page, run it in your terminal, and restart Claude Code. Skills live in ~/.claude/skills/ (global) or .claude/skills/ inside a project.

Can I use HTML CSS First with Cursor, Copilot, Gemini CLI, Codex or other AI tools?

The SKILL.md format is native to Claude (Claude Code, Desktop, claude.ai). The instructions inside adapt to other assistants: Cursor rules, GitHub Copilot instructions, Windsurf rules, Custom GPTs, AGENTS.md for OpenAI Codex, and GEMINI.md for Google Gemini CLI — our conversion guides cover each, and the free converter on the tools page does the wrapping for you.

HTML CSS First

Pushes frontend builds toward native HTML/CSS (details, popover, :has(), scroll-driven animation) before reaching for JS.

by macdonst · macdonst/html-css-first

Tested · Works

Install — copy the command Download source ↗

Test report

Verdict: Tested · Works
Score: 9.2/10
Tested: Jul 16, 2026
Environment: Claude Code 2.x (agent harness)
Upstream re-checked: Aug 10, 2026 · 2197866

Built and rendered the same FAQ accordion twice in a real browser: the baseline JS version needs ~15 lines of click-handler code and goes completely dead with JS disabled, while the skill's <details name="faq"> version gets smooth CSS animation AND native mutually-exclusive open/close for free, verified live with zero JavaScript attached.

Scored on four weighted criteria — install, triggering, output vs. baseline, docs. How scoring works

Installs cleanly 5/5
Triggers reliably 5/5
Output vs. baseline 9/10
Docs & honesty 4/5

What HTML CSS First does

A frontend code-review and build reference that checks, before writing or approving any JS-heavy UI pattern, whether a native HTML element or modern CSS feature already does the job - modals via dialog/popover, accordions via details, tabs via radio+:has(), form validation via constraint-validation attributes. Triggers on building or reviewing UI components (modals, accordions, tabs, tooltips, dropdowns, carousels, sticky headers) or 'how do I build X in the browser' questions.

How to install HTML CSS First

git clone https://github.com/macdonst/html-css-first.git
cd html-css-first
mkdir -p ~/.claude/skills
cp -r . ~/.claude/skills/html-css-first

Skills live in ~/.claude/skills/ (global) or .claude/skills/ (per-project). Restart Claude Code after installing.

Commands — how to trigger HTML CSS First

/html-css-first Pushes frontend builds toward native HTML/CSS (details, popover, :has(), scroll-driven animation) before reaching for JS.

It also activates on plain-language prompts like these:

Build a FAQ accordion that only opens one item at a time, no JS needed
Review this modal component and tell me if I can drop the JavaScript
How do I build tabs using just radio buttons and CSS instead of JS

Frequently asked questions

Is the HTML CSS First skill free?: Yes. The skill itself is free from macdonst/html-css-first. SkillProof publishes the install command and an independent test verdict at no cost.
Does HTML CSS First work with Claude Code?: We tested it with Claude Code 2.x (agent harness) on Jul 16, 2026. Verdict: Tested · Works. Built and rendered the same FAQ accordion twice in a real browser: the baseline JS version needs ~15 lines of click-handler code and goes completely dead with JS disabled, while the skill's <details name="faq"> version gets smooth CSS animation AND native mutually-exclusive open/close for free, verified live with zero JavaScript attached.
What is the HTML CSS First SkillProof Score?: 9.2/10 — installs cleanly 5/5, triggers reliably 5/5, output vs. baseline 9/10, docs & honesty 4/5.
How do I install HTML CSS First?: Copy the install command from this page, run it in your terminal, and restart Claude Code. Skills live in ~/.claude/skills/ (global) or .claude/skills/ inside a project.
Can I use HTML CSS First with Cursor, Copilot, Gemini CLI, Codex or other AI tools?: The SKILL.md format is native to Claude (Claude Code, Desktop, claude.ai). The instructions inside adapt to other assistants: Cursor rules, GitHub Copilot instructions, Windsurf rules, Custom GPTs, AGENTS.md for OpenAI Codex, and GEMINI.md for Google Gemini CLI — our conversion guides cover each, and the free converter on the tools page does the wrapping for you.