12 Best CSS FlexBox Essentials You Should Know
The CSS3 Flexible Box, or flexbox, is a layout mode providing for the arrangement of elements on a page such that the elements behave predictably when the page layout must accommodate different screen sizes and different display devices.
For many applications, the flexible box model provides an improvement over the block model in that it does not use floats, nor do the flex container’s margins collapse with the margins of its contents.
Default Block Css Display
This defines a flex container; inline or block depending on the given value. It enables a flex context for all its direct children.
Note that CSS columns have no effect on a flex container.
This establishes the main-axis, thus defining the direction flex items are placed in the flex container. Flexbox is (aside from optional wrapping) a single-direction layout concept. Think of flex items as primarily laying out either in horizontal rows or vertical columns.
By default, flex items will all try to fit onto one line. You can change that and allow the items to wrap as needed with this property.
This defines the alignment along the main axis. It helps distribute extra free space left over when either all the flex items on a line are inflexible, or are flexible but have reached their maximum size. It also exerts some control over the alignment of items when they overflow the line.
This defines the default behaviour for how flex items are laid out along the cross axis on the current line. Think of it as the justify-content version for the cross-axis (perpendicular to the main-axis).
This aligns a flex container’s lines within when there is extra space in the cross-axis, similar to how justify-content aligns individual items within the main-axis.
By default, flex items are laid out in the source order. However, the order property controls the order in which they appear in the flex container.
This defines the ability for a flex item to grow if necessary. It accepts a unitless value that serves as a proportion. It dictates what amount of the available space inside the flex container the item should take up.
If all items have flex-grow set to 1, the remaining space in the container will be distributed equally to all children. If one of the children has a value of 2, the remaining space would take up twice as much space as the others (or it will try to, at least).
This defines the ability for a flex item to shrink if necessary
This defines the default size of an element before the remaining space is distributed. It can be a length (e.g. 20%, 5rem, etc.) or a keyword. The auto keyword means “look at my width or height property” (which was temporarily done by the main-size keyword until deprecated). The content keyword means “size it based on the item’s content” – this keyword isn’t well supported yet, so it’s hard to test and harder to know what its brethren max-content, min-content, and fit-content do.
This allows the default alignment (or the one specified by align-items) to be overridden for individual flex items.
Please see the align-items explanation to understand the available values.
CSS FlexBox Essentials
- This post originally appeared on Im a Designer.