About

Layout prototyping often involves repetitive coding of placeholder elements. This tool mitigates that friction by generating a configurable set of DOM elements with precise geometric constraints. It serves as a visual sandbox for the CSS Box Model and layout algorithms (Flexbox/Grid).

By abstracting the code into visual controls, you can rapidly test responsiveness and spacing logic. The tool calculates the total occupied space using the formula W_total ≈ n × w + (n − 1) × gap, allowing for immediate validation of structural integrity before implementation. Perfect for wireframing, teaching CSS, or generating background patterns.

Formulas

When using Flexbox with justify-content: space-between, the browser automatically calculates the whitespace. The mathematical distribution of space S between n boxes in a container of width W is:

S = W − (n × w)n − 1

Where w is the width of a single box. If the result is negative (S < 0), the boxes will overflow or shrink (if flex-shrink is allowed).

Reference Data

CSS Property	Role	Value Range / Type	Default
display	Layout Context	flex, grid, block	flex
gap	Spacing	px, rem, %	20px
flex-wrap	Overflow Handling	nowrap, wrap	wrap
justify-content	X-Axis Alignment	start, center, space-between	center
align-items	Y-Axis Alignment	stretch, center, start	center
border-radius	Corner Curvature	0 − 50%	8px
box-shadow	Depth Perception	CSS Shadow Syntax	none

Frequently Asked Questions

In Flexbox mode, set "Justify" to "Space Between". This forces the browser to calculate equal spacing between elements. Alternatively, use "Grid" mode and define a fixed "Gap" (e.g., 20px) which guarantees a constant distance regardless of container size.

Yes. The output code uses standard, semantic HTML5 and CSS3. It avoids inline styles for the layout logic, providing a clean class-based structure that you can copy-paste directly into your stylesheet.

This is standard Flexbox behavior. The property `flex-shrink` defaults to 1. To prevent this, toggle the "Wrap" option to "On", which allows boxes to break onto a new line when the horizontal space W is exhausted.

Yes. Switch the "Layout Mode" to "Grid". The tool will automatically generate a responsive grid layout using `repeat(auto-fill, minmax(...))` logic, which is the modern standard for responsive cards.