home / skills / jwynia / agent-skills / shadcn-layouts
This skill helps you generate correct shadcn/Tailwind layouts by applying CSS layout mental models to ensure scrolling, height, and grid correctness.
npx playbooks add skill jwynia/agent-skills --skill shadcn-layoutsReview the files below or copy the command above to add this skill to your agents.
---
name: shadcn-layouts
description: "Generate correct shadcn/Tailwind layouts by applying CSS mental models. This skill should be used when the user asks to 'create a shadcn layout', 'fix layout issues', 'debug CSS height problems', 'make scrolling work', or has issues with Tailwind flex/grid. Keywords: shadcn, Tailwind, layout, CSS, flex, grid, height, scroll, overflow."
license: MIT
compatibility: Works with shadcn/ui, Tailwind CSS v3/v4, React, Next.js.
metadata:
author: jwynia
version: "1.0"
type: utility
mode: generative
domain: development
---
# shadcn/Tailwind Layouts
Help generate shadcn/Tailwind components that render correctly the first time. Most agent-generated UI fails due to missing mental models about how CSS layout works—not syntax errors, but assumption gaps.
## When to Use This Skill
Use this skill when:
- Creating shadcn/Tailwind layouts
- Debugging height/scroll issues
- Fixing flex/grid problems
- Setting up full-page app shells
Do NOT use this skill when:
- Writing backend code
- Working on non-Tailwind CSS projects
- Designing (use frontend-design first)
## Core Principle
**CSS layout flows from constraints. Height flows down from explicit ancestors. Width flows up from content. Agents fail because they apply classes without understanding the constraint chain.**
## Critical Mental Models
### Model 1: Height Inheritance Chain
`h-full` means `height: 100%`. 100% of what? **100% of the parent's computed height.**
```
BROKEN (chain incomplete):
<html> <!-- no height -->
<body> <!-- no height -->
<div class="h-full"> <!-- 100% of nothing = 0 -->
WORKING (chain complete):
<html class="h-full"> <!-- 100% of viewport -->
<body class="h-full"> <!-- 100% of html -->
<div class="h-full"> <!-- 100% of body = works -->
```
**Rule:** Trace from element up to `<html>`. Every ancestor needs explicit height, OR use viewport units (`h-screen`) to break the chain.
### Model 2: Flex Overflow Gotcha
Flex children have implicit `min-height: auto`, preventing shrinking below content size.
```tsx
// BROKEN (won't scroll)
<div className="flex flex-col h-screen">
<main className="flex-1 overflow-y-auto"> {/* Can't shrink! */}
// WORKING (scrolls correctly)
<div className="flex flex-col h-screen">
<main className="flex-1 overflow-y-auto min-h-0"> {/* Can shrink */}
```
**Rule:** Flex children that scroll need `min-h-0`. Children that shouldn't shrink need `shrink-0`.
### Model 3: Grid Parent/Child Separation
Grid is defined on the **parent**. Children just occupy cells.
```tsx
// BROKEN
<div className="grid-cols-3"> {/* Missing 'grid'! */}
// WORKING
<div className="grid grid-cols-3"> {/* 'grid' enables grid-cols-* */}
```
**Rule:** `flex` or `grid` must be declared on parent before direction/template classes work.
### Model 4: Scroll Container Dimensions
Scroll containers need **explicit dimensions** to know when to scroll.
```tsx
// BROKEN (never scrolls)
<ScrollArea> {/* No height constraint */}
// WORKING (flex-constrained)
<div className="flex flex-col h-screen">
<ScrollArea className="flex-1 min-h-0">
```
## Diagnostic States
### SL1: Height Chain Broken
**Symptoms:** Elements collapse, `h-full` not working
**Fix:** Trace to html, add heights or use `h-screen`
### SL2: Flex Overflow Blocked
**Symptoms:** Scroll doesn't work, content overflows
**Fix:** Add `min-h-0` to flex children that scroll
### SL3: Grid Structure Wrong
**Symptoms:** Items stack vertically instead of columns
**Fix:** Ensure `grid grid-cols-*` on parent
### SL4: Styles Not Applying
**Symptoms:** Unstyled components, colors wrong
**Fix:** Check Tailwind content paths, CSS variables in globals.css
### SL5: Component Dependencies Missing
**Symptoms:** "Module not found", functionality broken
**Fix:** `npx shadcn add [component]`, install peer deps
## Common Layout Patterns
### Full-Page App Shell
```tsx
// layout.tsx
<html lang="en" className="h-full">
<body className="h-full">{children}</body>
</html>
// page.tsx
<div className="flex h-full">
<aside className="w-64 shrink-0 border-r overflow-y-auto">
<nav>...</nav>
</aside>
<main className="flex-1 min-w-0 overflow-y-auto">
{children}
</main>
</div>
```
### Dashboard with Header
```tsx
<div className="flex flex-col h-screen">
<header className="h-16 shrink-0 border-b">...</header>
<div className="flex flex-1 min-h-0">
<aside className="w-64 shrink-0 border-r overflow-y-auto">...</aside>
<main className="flex-1 min-w-0 overflow-y-auto p-6">
{children}
</main>
</div>
</div>
```
### Card Grid
```tsx
<div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-6">
{items.map(item => (
<Card key={item.id}>
<CardHeader><CardTitle>{item.title}</CardTitle></CardHeader>
<CardContent>{item.content}</CardContent>
</Card>
))}
</div>
```
## Anti-Patterns
### The Height Assumption
Using `h-full` without verifying ancestor chain.
**Fix:** Trace to html. Use `h-screen` to break chain.
### The Overflow Ignorance
Adding `overflow-y-auto` without `min-h-0` on flex children.
**Fix:** Flex children need `min-h-0` to shrink.
### The Import Guess
Guessing import paths like `shadcn/ui`.
**Fix:** Check `components.json` for alias. Usually `@/components/ui/*`.
### The Flat Compound
Flattening compound components (Dialog without DialogTrigger/DialogContent).
**Fix:** Maintain required nesting structure.
## Pre-Generation Checklist
- [ ] Import alias known (`@/components/ui/*`)
- [ ] html has `h-full`
- [ ] body has `h-full` or `min-h-full`
- [ ] Scroll containers have explicit height
- [ ] Flex scroll children have `min-h-0`
- [ ] Fixed elements have `shrink-0`
## Related Skills
- **frontend-design** - Design decisions before implementation
- **react-pwa** - PWA features for React apps
This skill generates correct shadcn/Tailwind layouts and fixes common layout failures by applying clear CSS mental models. It focuses on practical fixes for height chains, flex/grid behaviors, overflow, and scroll containers so components render correctly the first time. Use it to get layout code that follows Tailwind patterns and shadcn component expectations.
I inspect the constraint chain for height and the parent layout context (flex or grid) to determine why an element is collapsing, overflowing, or not scrolling. The skill adds or recommends specific Tailwind utilities (h-full, h-screen, min-h-0, min-w-0, shrink-0, grid) and the correct parent-level classes to restore expected behavior. It also checks for missing component dependencies and common Tailwind configuration issues.
Why does h-full render as zero height?
h-full is 100% of the parent's computed height. If ancestors don't have explicit heights (or h-full/h-screen), 100% resolves to zero. Add heights up the chain or use h-screen on the constrained ancestor.
My scroll container doesn't scroll inside a flex column — what's missing?
Flex children default to min-height: auto, which prevents shrinking. Add min-h-0 to the flex child that should scroll and ensure its parent has an explicit height (h-screen or h-full chain).