Why isn't align-content working in my flexbox layout?

align-content only has an effect when flex-wrap is set to wrap or wrap-reverse and there are actually enough items to wrap onto multiple lines. On a single line, use align-items instead — that's the property that governs cross-axis alignment when there's only one row.

What does flex: 1 actually mean?

It's shorthand for flex: 1 1 0% — the item can grow, can shrink, and starts from a zero basis. When several items share flex: 1, they split the available space evenly, ignoring their content width.

How do I center a div both horizontally and vertically with flexbox?

On the parent container, set display: flex; justify-content: center; align-items: center. The container needs a defined height (or needs to fill its own parent) for vertical centering to actually be visible.

How does the flexbox order property work?

order reorders items visually without touching the HTML. Every item defaults to order: 0, and lower values are placed first. It only affects visual position — tab order and screen-reader order still follow the DOM, which is worth checking for accessibility.

Why won't my flex items shrink below their content size?

By default, flex items have min-width: auto (or min-height: auto in column layouts), which prevents them from shrinking past their content's natural size even with flex-shrink set. Add min-width: 0 (or min-height: 0) to the item to let it shrink further, which is especially common when text or images overflow a flex child.

CSS Flexbox Generator

Free CSS Flexbox generator: live preview, Tailwind & CSS dual output, 10 preset layouts, contextual warnings, React/JSX export. No signup required.

Updated June 2026

Preset Layouts

Container Controls

display flex

flex-direction row

flex-wrap nowrap

justify-content flex-start

align-items stretch

align-content stretch

Requires flex-wrap: wrap

gap 16px

Live Preview

3/8

Code Output

flex
gap-4

Manual Overrides

gap 16px

Border Radius

Item Controls

Click an item in the preview to edit its properties.

How to use the CSS flexbox generator

From a preset to production-ready code in under a minute

1. Pick a preset

Navbar, Card Grid, Sidebar, Holy Grail — the live preview and the code update immediately.

2. Adjust the container and items

Tune flex-direction, justify-content, align-items — or click an item in the preview to edit its grow, shrink, and order.

3. Copy the code

Switch between Tailwind, plain CSS, or React/JSX and copy it, or download the CSS file directly.

What this flexbox generator does

Dual output, plus warnings that explain themselves

Tailwind and CSS side by side

See both output formats at the same time, plus a dedicated React/JSX tab — most generators only give you one.

10 ready-made layout presets

Navbar, Centered Hero, Card Grid, Sidebar, Holy Grail, and more — start from a real-world pattern instead of a blank container.

Contextual warnings

When a property has no effect in the current configuration — like align-content without flex-wrap — the tool tells you exactly why.

Per-item editing

Click any box in the preview to edit its flex-grow, flex-shrink, flex-basis, align-self, and order individually.

One-click copy or download

Copy the generated code straight to your clipboard, or download it as a ready-to-use .css file.

Examples

Common layout patterns and the CSS they produce

Pattern

Generated CSS

Navbar

display:flex; justify-content:space-between; align-items:center; gap:16px

Centered hero

display:flex; justify-content:center; align-items:center

Wrapping card grid

display:flex; flex-wrap:wrap; gap:16px

Sidebar + content

display:flex; [sidebar] flex:0 0 auto; [content] flex:1 1 0%

When you'll reach for this

The most common scenarios developers use this generator for

Navbars

flex plus justify-content: space-between and align-items: center — logo on the left, nav links on the right, in one line.

Centering an element

The fastest way to center a div on both axes without margin hacks or absolute positioning.

Card grid rows

flex-wrap: wrap plus gap — cards reflow onto the next line automatically as the viewport shrinks.

Sidebar layouts

One fixed-width panel and another that grows to fill the remaining space with flex-grow: 1.

Handing off React components

Grab the JSX/inline-style output when you need flex layout logic dropped straight into a component, not a stylesheet.

Common mistakes

The flexbox gotchas that trip up most developers

Confusing justify-content with align-items

justify-content controls the main axis; align-items controls the cross (perpendicular) axis. Which one is 'horizontal' flips when you switch flex-direction to column.

Setting align-content without flex-wrap: wrap

align-content only has an effect once items have actually wrapped onto multiple lines — the tool flags this automatically when it applies to your layout.

Expecting order to change DOM order

order only changes the visual position of an item. Tab order still follows the source DOM, which matters for keyboard navigation and accessibility.

Why use this flexbox generator

It shows Tailwind classes and plain CSS at the same time — most flexbox generators force you to pick one output format and start over if you need the other.

The contextual warnings explain exactly why a property isn't doing anything, cutting out the trial-and-error most developers hit with align-content and flex-wrap on their first few layouts.

Flexbox vs. CSS Grid

When to reach for each one

Flexbox

CSS Grid

Dimensions

One-dimensional (a single row OR column)

Two-dimensional (rows AND columns)

Best for

Navbars, alignment inside a single component

Page-level, macro layout

Typical usage

Inside individual components or sections

The overall page structure

Frequently asked questions

justify-content controls the main axis — horizontal when flex-direction is row, vertical when it's column. align-items controls the cross axis, perpendicular to that. To center an element on both axes, set both properties to center.

References

MDN — CSS Flexible Box Layout

The complete specification reference, with browser compatibility data for every property.

CSS-Tricks — A Complete Guide to Flexbox

The most widely referenced visual guide covering every flexbox property with diagrams.