Flexing your CSS muscles

Basics of using flexbox to style your site

For parents(flex container)

flex-direction

This sets-up the main-axis, by defining the direction flex items are placed in the flex container. Flexbox is 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 in ltr; right to left in rtl
• row-reverse: right to left in ltr; left to right in rtl
• column: same as row but top to bottom
• column-reverse: same as row-reverse but bottom to top

flex-wrap

Flex items will naturally try to fit into one line. You can change that and allow the items to wrap.

.container {
  flex-wrap: nowrap | wrap | wrap-reverse;
}

• 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.

justify-content

This establishes 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.

.container {
  justify-content: flex-start | flex-end | center | space-between | space-around | space-evenly | start | end | left | right ... + safe | unsafe;
}

• 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.

align-item

Establishes 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.

.container {
  align-items: stretch | flex-start | flex-end | center | baseline | first baseline | last baseline | start | end | self-start | self-end + ... safe | unsafe;
}

• 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

align-content

This establishes the alignment along the cross 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.

.container {
  align-content: flex-start | flex-end | center | space-between | space-around | space-evenly | stretch | start | end | baseline | first baseline | last baseline + ... safe | unsafe;
}

• 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

For Children (flex items)

flex-grow

This dictates what amount of the available space inside the flex container the item should take up. If all of the items within the flex container are equal to 1, they will all be relatively equal in size. However, if one item has a value of 2, it will be twice the size of the adjoining items.

.item {
  flex-grow: 4; /* default 0 */
}

flex-shrink

This is the ability of an item to shrink based on items surrounding it.

.item { 
flex-shrink: 3; /* default 1 */ 
}

align-self

This allows for the default alignment for a single item to be overridden

.item {
  align-self: auto | flex-start | flex-end | center | baseline | stretch;
}

These are just a few of the ways you can flex your CSS muscles. For more information about flex box please visit

Basic concepts of flexbox

Flexbox Froggy

Some content was sourced from CSS-Tricks.com & flexboxfroggy.com