Basic
Since flexbox is a whole module and not a single property, it involves a lot of things including its whole set of properties. Some of them are meant to be set on the container (parent element, known as “flex container”) whereas the others are meant to be set on the children (said “flex items”).
Flexbox properties
Properties for the Parent(flex container)
**Properties for the Children
(flex items)**
flex-direction
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.
.container { flex-direction: row | row-reverse | column | column-reverse; }
row
(default): left to right inltr
; right to left inrtl
row-reverse
: right to left inltr
; left to right inrtl
column
: same asrow
but top to bottomcolumn-reverse
: same asrow-reverse
but bottom to top
flex-wrap
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.
nowrap
(default): all flex items will be on one linewrap
: flex items will wrap onto multiple lines, from top to bottom.wrap-reverse
: flex items will wrap onto multiple lines from bottom to top.
flex-flow
This is a shorthand for the flex-direction
and flex-wrap
properties, which together define the flex container’s main and cross axes. The default value is row nowrap
.container { flex-flow: column wrap; }
justify-content
This defines the alignment along the main axis. It helps distribute extra free space leftover 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.
flex-start
(default): items are packed toward the start of the flex-direction.flex-end
: items are packed toward the end of the flex-direction.start
: items are packed toward the start of thewriting-mode
direction.end
: items are packed toward the end of thewriting-mode
direction.left
: items are packed toward left edge of the container, unless that doesn’t make sense with theflex-direction
, then it behaves likestart
.right
: items are packed toward right edge of the container, unless that doesn’t make sense with theflex-direction
, then it behaves likeend
.center
: items are centered along the linespace-between
: items are evenly distributed in the line; first item is on the start line, last item on the end linespace-around
: items are evenly distributed in the line with equal space around them. Note that visually the spaces aren’t equal, since all the items have equal space on both sides. The first item will have one unit of space against the container edge, but two units of space between the next item because that next item has its own spacing that applies.space-evenly
: items are distributed so that the spacing between any two items (and the space to the edges) is equal.
align-items
This defines the default behavior 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).
stretch
(default): stretch to fill the container (still respect min-width/max-width)flex-start
/start
/self-start
: items are placed at the start of the cross axis. The difference between these is subtle, and is about respecting theflex-direction
rules or thewriting-mode
rules.flex-end
/end
/self-end
: items are placed at the end of the cross axis. The difference again is subtle and is about respectingflex-direction
rules vs.writing-mode
rules.center
: items are centered in the cross-axisbaseline
: items are aligned such as their baselines align