Subgrid
DesignsubgridSubgrid is an Agent Skill for design published in the thedaviddias/Front-End-Checklist repository on GitHub: a SKILL.md instruction file an AI agent can load to do this task.
Use when reviewing card grid layouts with misaligned content areas, or any nested grid where child items need to align with sibling cards' corresponding sections without JavaScript intervention.
How to use this skill
Bring this guide into your coding agent with a prompt tailored to the tool you use.
- Open your project in Codex.
- Copy and paste the prompt below.
- Review files and risks before approving any action.
Inspect the Agent Skill at https://github.com/thedaviddias/Front-End-Checklist/blob/HEAD/skills/subgrid/SKILL.md and all supporting files. Report provenance, permissions, scripts, dependencies, and security risks. Propose an exact installation into .agents/skills/subgrid, but wait for my approval before writing files or running scripts.
Copying this prompt does not install or run the skill. Review third-party files before use.
Use CSS subgrid to align nested grid items to parent tracks
Card grids are one of the most common UI patterns, but aligning content across cards — matching title heights, content areas, and footers — has historically required JavaScript height measurement or CSS hacks. Subgrid solves this at the layout engine level: nested items participate directly in the parent grid's tracks, so alignment is automatic, performant, and CSS-only.
Quick Reference
- subgrid lets a nested grid inherit its parent grid tracks instead of creating new ones
- Solves misaligned card titles, content, and footers across rows of cards
- No JavaScript height matching needed — the browser handles track alignment
- Universal support: Safari 16+, Chrome/Edge 117+, Firefox 71+
Check
Look for card grid layouts in this CSS where card content areas (titles, body text, footers) might not align across cards of different content lengths. These are candidates for subgrid.
Fix
Convert this card grid to use subgrid. Show how to set grid-template-rows on the parent grid, then apply grid-row: span N and grid-template-rows: subgrid on each card to inherit the parent tracks.
Explain
Explain how CSS subgrid works, how it differs from a nested grid, what problem it solves with card alignment, and when to use subgrid on columns versus rows.
Code Review
Review card grid and nested grid layouts in this stylesheet. Flag any layout that uses JavaScript height matching, fixed heights, or display: contents workarounds to achieve cross-card alignment — and show the subgrid equivalent.
For full implementation details, code examples, and framework-specific guidance,
see references/rule.md.
Rule page: https://frontendchecklist.io/en/rules/css/subgrid