b2KIT

Page Layout Generator

Generate common page layouts (sidebar + content, 3-column, masonry) with CSS Grid or Flexbox code.

Tested tool guide Tested browser tools Checked August 16, 2026

What Page Layout Generator does, with a checked example

This tool builds the HTML skeleton and matching CSS for a page layout pattern you pick from a short list: sidebar plus content, holy-grail three-column, equal-width columns, or masonry. You set the structural numbers (sidebar width, column count, gap) and choose CSS Grid or Flexbox as the mechanism; the tool emits the container and child rules that implement it. The most common surprise is that masonry output either relies on the CSS masonry value, which is not supported in every shipping browser, or falls back to a column-based approximation that reorders items differently than true masonry packing.

Worked example

A concrete input and expected output from the current implementation.

Input

Layout: Sidebar + content, Sidebar width: 240px, Gap: 24px, Method: Flexbox

Expected output

.layout {
  display: flex;
  gap: 24px;
}

.sidebar {
  flex: 0 0 240px;
}

.content {
  flex: 1 1 0%;
  min-width: 0;
}

Flexbox with a fixed-basis sidebar (flex: 0 0 240px) and a growing content pane (flex: 1 1 0%) reproduces a classic sidebar layout; min-width: 0 on .content is required so its text and flex children can shrink below their intrinsic width instead of overflowing.

How the result is produced

1

Layout pattern selection

You pick one pattern (sidebar+content, three-column holy-grail, N equal columns, or masonry) and a small set of parameters specific to it: sidebar width or column count, gap size, and unit (px, rem, or %). Changing the pattern swaps both the HTML skeleton's class structure and the CSS rule set, not just values.

2

Grid vs. Flexbox output

The same pattern can be generated as CSS Grid (using grid-template-columns and named areas for holy-grail layouts) or Flexbox (using flex-basis and flex-grow on children). Grid output is generally shorter for fixed multi-track layouts; Flexbox output is used for the masonry fallback and simpler two-pane cases.

Good uses

  • starting a new page section with a sidebar and main content area without hand-writing the flex or grid boilerplate
  • getting a holy-grail (header, footer, left nav, right aside, center content) skeleton with the CSS areas already wired to the right HTML elements
  • comparing how the same layout looks expressed in Grid versus Flexbox before committing to one in a component library

Limits and checks

  • generated masonry CSS either depends on the still-unevenly-supported CSS grid-template-rows: masonry feature or uses a column-count approximation that fills top-to-bottom in a different item order than a true masonry algorithm - check which one you got
  • the output has no media queries; a sidebar layout that looks right at desktop width will not collapse to a single column on narrow viewports unless you add breakpoints yourself
  • class names in the skeleton (.layout, .sidebar, .content, etc.) are generic and will collide with existing classes of the same name in your stylesheet if pasted in without renaming

Common questions

Does it generate the responsive breakpoints for mobile too?

No. The tool outputs the desktop-width layout rules only; there are no media queries in the generated CSS. You need to add your own breakpoint that switches, for example, a flex-direction: row sidebar layout to column below a chosen width.

Can I get true CSS masonry instead of the column-based fallback?

The tool can emit the native masonry grid syntax, but that property is only implemented in some browsers as of this writing (notably not yet in all Chromium-based browsers), so for broad compatibility the generator defaults to a multi-column fallback unless you explicitly request the native syntax.

References and verification

The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.

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