Flexbox Generator
Generate Flexbox code interactively
Online CSS Flexbox Generator - Learn and Generate Code
What is CSS Flexbox and why is it essential for modern layouts?
CSS Flexbox (Flexible Box Layout) is a one-dimensional layout model designed to distribute space and align content efficiently, even when element sizes are dynamic or unknown. It solves classic CSS problems that used to require hacks: perfect vertical centering in a single line of code, even distribution of space between elements, visual reordering without touching the HTML, and elements that adapt fluidly to different container sizes. Flexbox works along a main axis and a cross axis, with properties for both the parent flex container and the child flex items.
What are the essential flex container properties?
A flex container is created with display: flex (or inline-flex) and governs the behaviour of all its direct children. The key properties are flex-direction (row, column, row-reverse, column-reverse), which sets the main axis; justify-content (flex-start, center, flex-end, space-between, space-around, space-evenly), which distributes space along the main axis; align-items (stretch, flex-start, center, flex-end, baseline), which aligns items on the cross axis; flex-wrap (nowrap, wrap, wrap-reverse), which controls whether items move to new lines; align-content, which distributes space between lines when wrapping; and gap, which adds uniform spacing between items.
When should you use Flexbox instead of CSS Grid?
Flexbox is the right tool for one-dimensional layouts where content flows in a single direction: navigation bars and menus, cards in a row or column, lists with variable-sized items, aligned form components, and any case where items should adapt to the available space. CSS Grid is better for two-dimensional layouts where rows AND columns are defined at once: complex page layouts, dashboards, galleries with precise placement, and anything needing control over both dimensions. In practice you use both: Grid for the overall page structure and Flexbox inside the components.
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Frequently asked questions
Why do my flex items refuse to shrink past a certain point?
By default flex-shrink is 1, which allows shrinking, but flex-basis is auto, meaning the size comes from the content. If the content has an implicit min-width, such as long unbreakable text, an image or an input, the item will not shrink below that minimum. The fixes are to add min-width: 0 to the flex item to override the implicit minimum, use overflow: hidden to contain the content, or apply word-break: break-word to the text. It is one of the most common Flexbox gotchas.
How do I center an element vertically and horizontally with Flexbox?
It is trivial with Flexbox, which is exactly what used to require hacks. On the parent container set display: flex; justify-content: center; align-items: center; and make sure the container has a height (height: 100vh for a full viewport). An alternative for a single child is display: flex on the parent plus margin: auto on the child. If you only need horizontal centering, justify-content: center is enough on its own.
What exactly does flex: 1 mean and when should I use it?
flex: 1 is shorthand for three properties: flex-grow: 1, so the item grows to fill the available space; flex-shrink: 1, so the item shrinks when needed; and flex-basis: 0%, so the item starts from a zero base size before the space is distributed. When several items carry flex: 1 they split the available space evenly. It is ideal for equal-width adaptive columns, or for making one element fill the remaining space, such as the main content between a header and a footer.