Flexbox Generator

Visualizing CSS Flexbox Layouts

CSS Flexbox provides a one-dimensional layout model that distributes space along a main axis and a cross axis. Designing these layouts in code often requires trial and error to balance container-level rules with individual item overrides.

Using an interactive tool makes the relationship between parent and child properties immediate. Adjusting the controls updates a live visual preview, showing how items expand, shrink, wrap, and align. Once the layout matches your design requirements, you can copy the clean, optimized CSS code directly into your stylesheet.

Container Properties and Axis Dynamics

The behavior of a flex layout is governed by the properties set on the parent container. These properties establish the direction of the flow, wrapping behavior, spacing, and alignment.

Direction and Axis Swapping

The Direction property determines the main axis along which the flex items are laid out:

• Row: Items flow horizontally from left to right.
• Row reverse: Items flow horizontally from right to left.
• Column: Items flow vertically from top to bottom.
• Column reverse: Items flow vertically from bottom to top.

Switching the direction from row to column swaps the main and cross axes. This swap fundamentally changes how alignment properties function. For example, when the direction is set to Row, horizontal alignment is controlled by Justify content and vertical alignment by Align items. When switched to Column, Justify content governs vertical alignment, while Align items manages horizontal alignment.

Wrapping and Multi-Line Alignment

The Wrap property controls whether items are forced onto a single line or allowed to break onto multiple lines:

• No wrap: All items are forced onto one line, even if they overflow the container.
• Wrap: Items that do not fit drop down to the next line.
• Wrap reverse: Items wrap onto new lines flowing upward or in reverse order.

When wrapping is enabled and items span multiple lines, the Align content property becomes active. This property spaces and aligns these lines as a group within the container. If wrapping is disabled, Align content has no effect on the layout.

Spacing and Alignment Controls

The container controls offer precise placement options for distributing items and managing empty space:

Managing Individual Flex Items

While container properties set the global layout rules, you can fine-tune individual items to behave differently from their siblings. Clicking Add item generates a new item in the preview (such as Item 5).

Each item has its own set of properties that control its sizing, ordering, and alignment:

• Order: A numerical value that changes the visual sequence of the item. This allows you to move an item earlier or later on the screen without altering the underlying HTML structure.
• Grow: A numerical value defining the item's ability to expand and fill available empty space along the main axis relative to the other items.
• Shrink: A numerical value defining the item's ability to contract when the container space is tight, preventing overflow.
• Basis: A numerical value or Auto that sets the initial main-size of the item before any growing or shrinking occurs.
• Align self: Auto, Start, End, Center, Stretch, Baseline. This overrides the container's Align items value for this specific item, allowing it to align differently along the cross axis.

To keep your stylesheet clean, the generator only outputs CSS rules for individual items that have had their default properties modified. Items left at their default settings do not receive redundant CSS rules.

Common Flexbox Layout Patterns

Flexbox is highly effective for building common user interface components. The generator allows you to visualize and build these structures quickly:

• Center: Perfect for centering a single element or a group of elements both horizontally and vertically within a container.
• Navbar: Distributes navigation links evenly across a header, often pushing the logo to one side and utility links to the other.
• Stack: Arranges elements vertically in a clean column with consistent spacing, ideal for forms, card content, or mobile menus.
• Cards: Creates a grid-like wrap of content blocks that automatically flow to the next line as the viewport shrinks.
• Sidebar: Sets up a two-column layout where a narrow sidebar sits next to a flexible main content area that expands to fill the remaining space.

Browser-Based Processing and Privacy

Your layout is built right in your browser. Nothing you set here is uploaded to BroBroGo. All calculations, visual rendering, and CSS generation happen locally on your device, ensuring your design configurations remain entirely private.

Once your layout is complete, clicking Copy CSS copies the generated code to your clipboard and changes the button state to Copied for immediate feedback.

Frequently Asked Questions

What is the difference between justify-content and align-items?

Justify-content spaces the items along the main axis — the direction the row or column flows — while align-items positions them across the other axis. Switch the direction from row to column and the two axes swap, so justify-content starts working top to bottom and align-items left to right.

How do the per-item controls work?

Pick an item by its number, then set how much it grows to fill spare space, how much it shrinks when space is tight, its starting size (basis) and its own cross-axis alignment. Order moves an item earlier or later on screen without touching the HTML. Only the items you actually change get their own rule in the CSS.

When do wrap and align-content matter?

With wrapping off, every item is forced onto one line and can be squeezed narrower. Turn it on and items that no longer fit drop to the next line — that is when align-content takes over, spacing the lines as a group. Gap sets the space between items, and between lines, without margins.