Flex like a Flexbox

Flexbox aims at providing a more efficient way to lay out, align and distribute space among items in a container, even when their size is unknown and/or dynamic (thus the word “flex”). The main idea behind the flex layout is to give the container the ability to alter its items’ width/height (and order) to best fill the available space (mostly to accommodate to all kind of display devices and screen sizes). A flex container expands items to fill available free space or shrinks them to prevent overflow.

Flexbox layout is most appropriate to the components of an application, and small-scale layouts, while the Grid layout is intended for larger scale layouts.

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”).

1. Declaring a Flexbox

A flexbox is declared to the flex container (or) a parent element, using the display property. By default, flex arranges the child items (or) flex items row-wise. But this can be changed suing the flex-direction property. This establishes the main-axis, thus defining the direction flex items are placed in the flex container. flex-direction can have 4 values,

• row (default): left to right in
• row-reverse: right to left
• column: same as row but top to bottom
• column-reverse: same as row-reverse but bottom to top

Syntax

.container {
  display: flex; /* or display: inline-flex */
    flex-direction: row;
}

2. 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. Also flex-wrap is applied on the parent element. flex-wrap can have 3 properties,

• nowrap (default): all flex items will be on one line.
• wrap: flex items will wrap onto multiple lines, from top to bottom.
• wrap-reverse: flex items will wrap onto multiple lines from bottom to top.

Syntax

.container {
  flex-wrap: wrap;
}

3. 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. flex-flow can have all combinations of flex-direction and flex-wrap.

Syntax

.container {
  flex-flow: column wrap;
}

4. Justify content

justify-content 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. justify-content can have the below values,

• 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 the writing-mode direction.
• end: items are packed toward the end of the writing-mode direction.
• left: items are packed toward left edge of the container, unless that doesn’t make sense with the flex-direction, then it behaves like start.
• right: items are packed toward right edge of the container, unless that doesn’t make sense with the flex-direction, then it behaves like start.
• center: items are centered along the line
• space-between: items are evenly distributed in the line; first item is on the start line, last item on the end line
• space-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.

Syntax

.container {
  justify-content: flex-start;
}

5. Align items

align-items 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-contentversion for the cross-axis (perpendicular to the main-axis). It can have the below values,

• 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 the flex-direction rules or the writing-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 respecting flex-direction rules vs. writing-mode rules.
• center: items are centered in the cross-axis
• baseline: items are aligned such as their baselines align

Syntax

.container {
  align-items: flex-start;
}

6. Align content

align-content aligns a flex container’s lines within when there is extra space in the cross-axis, similar to how justify-contentaligns individual items within the main-axis. It can have the following values,

• normal (default): items are packed in their default position as if no value was set.
• flex-start / start: items packed to the start of the container. The (more supported) flex-start honors the flex-direction while start honors the writing-mode direction.
• flex-end / end: items packed to the end of the container. The (more support) flex-end honors the flex-direction while end honors the writing-mode direction.
• center: items centered in the container
• space-between: items evenly distributed; the first line is at the start of the container while the last one is at the end
• space-around: items evenly distributed with equal space around each line
• space-evenly: items are evenly distributed with equal space around them
• stretch: lines stretch to take up the remaining space

Syntax

.container {
  align-content: flex-start;
}

7. Gap

The gap property explicitly controls the space between flex items. It applies that spacing only between items not on the outer edges.

Syntax

.container {
  display: flex;
  gap: 10px;
  gap: 10px 20px; /* row-gap column gap */
  row-gap: 10px;
  column-gap: 20px;
}