Flexbox Generator

About Flexbox generator

Try every flexbox alignment property on a set of numbered, colored boxes and copy the container CSS once the layout looks right. It is built for people who cannot remember whether justify-content or align-items controls the vertical direction, and it shows the answer live.

How to use it

1. Set flex-direction to row, row-reverse, column or column-reverse.
2. Choose flex-wrap: nowrap, wrap or wrap-reverse.
3. Pick justify-content and align-items values from the option rows.
4. When wrapping is on, an extra align-content row appears. Choose its value too.
5. Use the Items slider (1 to 8) and the Gap slider (0 to 40 px), then copy the CSS.

A centered vertical stack

column, nowrap, justify-content center, align-items center, gap 8

display: flex;
flex-direction: column;
flex-wrap: nowrap;
justify-content: center;
align-items: center;
gap: 8px;

When to use it

• Learning how the main axis flips when you change direction from row to column.
• Centering a card both horizontally and vertically inside a taller container.
• Spacing a navigation bar so the logo sits left and links sit right using space-between.
• Testing how wrapped rows distribute extra space with align-content.

Questions about Flexbox generator

Why does align-content disappear sometimes?

It only has an effect when items wrap onto more than one line. With nowrap the control is hidden and the property is left out of the CSS.

Which property controls which direction?

justify-content works along the main axis, which is horizontal for row and vertical for column. align-items works across it. Switching direction swaps what they do visually.

Does the output cover child properties like flex-grow?

No. It generates container rules only. Item settings such as flex, order and align-self are not included.

How are the preview items sized?

In row mode each box is 48 pixels wide with a 48 pixel minimum height and cannot shrink. In column mode they stretch to 100 percent width at a fixed 40 pixel height.

Is the gap property safe to use?

Gap for flex containers is supported in all current major browsers, so the generated declaration works without a fallback for modern audiences.

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