css-layout-helper

name

css-layout-helper

description

Creates CSS and Tailwind layout solutions for described UI patterns: grids, flex containers, sidebar layouts, card grids, sticky headers, centered content, and full-bleed sections. Use this skill whenever a user says "create a CSS layout for", "help me center this", "write CSS for a sidebar layout", "make a responsive grid", "how do I do a sticky header with scrollable content", "layout this page with CSS", "write Tailwind classes for this layout", or "fix my flexbox/grid layout". Also activate when someone shares a layout description or rough wireframe sketch. Supports plain CSS, CSS Grid, Flexbox, and Tailwind CSS v3/v4. Do NOT use for component-level styling (use react-component-generator) or animation (use animation-snippet-writer).

CSS Layout Helper

Build robust, responsive CSS layouts from descriptions — grids, flex containers, sticky elements, and full-page structures with clean, commented code.

When to Use

• Implementing a page layout from a design or description
• Fixing a broken flexbox or grid that isn't behaving as expected
• Building a responsive layout that adapts across screen sizes
• Creating reusable layout primitives (container, stack, sidebar)

When NOT to Use

• Component-level styling (colors, typography, spacing inside a component)
• Animation and transitions (use animation-snippet-writer)
• CSS-in-JS or Styled Components patterns (different approach)

---

Workflow

Step 1 — Understand the Layout

Ask the user to describe:

1. Layout type: Page layout / section / component layout
2. Structure: What elements are present? (header, sidebar, main, footer, etc.)
3. Responsive behavior: How does it change at mobile / tablet / desktop?
4. Sticky/fixed elements: Anything that stays on screen while scrolling?
5. CSS approach: Plain CSS / Tailwind / CSS Modules

Step 2 — Match to a Layout Pattern

Identify the appropriate CSS strategy:

Layout need	Best approach
Side-by-side two columns	Flexbox or Grid
Complex multi-area page	CSS Grid with named areas
Sticky sidebar + scrollable main	Grid with position: sticky
Centered content with max-width	Container utility
Card grid (auto-fill)	grid-template-columns: repeat(auto-fill, ...)
Equal-height columns	Flexbox align-items: stretch
Stack (vertical spacing)	Flexbox column with gap
Holy grail layout	CSS Grid 3-column + header/footer

Step 3 — Generate the Layout Code

Plain CSS Examples

Sidebar + Main (sticky sidebar):

.page-layout {
  display: grid;
  grid-template-columns: 260px 1fr;
  grid-template-rows: auto 1fr;
  grid-template-areas:
    "header header"
    "sidebar main";
  min-height: 100vh;
  gap: 0;
}

.header  { grid-area: header; }
.sidebar { grid-area: sidebar; position: sticky; top: 0; height: 100vh; overflow-y: auto; }
.main    { grid-area: main; padding: 1.5rem; }

@media (max-width: 768px) {
  .page-layout {
    grid-template-columns: 1fr;
    grid-template-areas:
      "header"
      "main";
  }
  .sidebar { display: none; } /* or slide-over — see below */
}

Responsive Card Grid:

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.5rem;
  padding: 1.5rem;
}

Centered Content Container:

.container {
  width: 100%;
  max-width: 1200px;
  margin-inline: auto;
  padding-inline: clamp(1rem, 4vw, 2rem);
}

Sticky Header + Scrollable Content:

.app-shell {
  display: grid;
  grid-template-rows: auto 1fr;
  height: 100vh;
  overflow: hidden;
}

.header {
  position: sticky;
  top: 0;
  z-index: 100;
}

.content {
  overflow-y: auto;
  padding: 1rem;
}

Tailwind CSS Examples

Sidebar + Main:

<div class="flex h-screen overflow-hidden">
  <!-- Sidebar -->
  <aside class="w-64 shrink-0 overflow-y-auto border-r bg-white lg:block hidden">
    <!-- nav items -->
  </aside>
  <!-- Main -->
  <main class="flex-1 overflow-y-auto p-6">
    <!-- content -->
  </main>
</div>

Responsive Card Grid:

<div class="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 xl:grid-cols-4 gap-6 p-6">
  <!-- cards -->
</div>

Centered container with padding:

<div class="mx-auto max-w-7xl px-4 sm:px-6 lg:px-8">
  <!-- content -->
</div>

Holy Grail Layout:

<div class="grid min-h-screen grid-rows-[auto_1fr_auto] grid-cols-[auto_1fr_auto]">
  <header class="col-span-3 ...">Header</header>
  <nav class="row-start-2 w-48 ...">Left Nav</nav>
  <main class="row-start-2 min-w-0 p-6">Main Content</main>
  <aside class="row-start-2 w-64 ...">Right Sidebar</aside>
  <footer class="col-span-3 ...">Footer</footer>
</div>

Step 4 — Explain the Key Decisions

For each layout, explain:

• Why Grid vs. Flexbox was chosen
• How the responsive behavior is handled
• What min-width: 0 or min-height: 0 fixes (overflow in grid items)

Step 5 — Call Out Common Pitfalls

• Grid/Flex items overflowing? Add min-width: 0 to the child
• Sticky not working? Parent must not have overflow: hidden
• 100vh too tall on mobile? Use 100dvh (dynamic viewport height)
• Cards not equal height? Parent needs align-items: stretch (default in grid)

---

Output Format

1. Layout HTML structure — semantic markup with classes
2. CSS / Tailwind — complete styles with comments
3. Responsive variants — mobile adjustments
4. Key decision notes — brief explanation of approach choices

---

Safety & Confirmation

• Test layouts across at least 3 breakpoints (320px mobile, 768px tablet, 1280px desktop).
• Flag if height: 100vh is used on mobile (recommend 100dvh or JS fallback).
• Always check that content can overflow gracefully without breaking the layout structure.