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  • 封じ込めの難しさ - サイトに予期できないコンテンツがある場合、フロートレイアウトを使うことが難しくになり、同時に維持するのが面倒になります。
  • ソースの順序依存性 - サイトのレイアウトはHTMLソースに依存するため、レスポンシブサイトはメディアクエリによるレイアウトの変更が難しくになります。
  • 同じ高さの列 - 様々なサイズのコンテンツを持つ2〜3列をコンテンツの大きさに関わらず同じ高さにすることが難しいです。
  • コンテンツのセンタリング - div内のコンテンツを垂直と水平方向の両方を中央に揃えるには、フロートを使用するのは非常に面倒です。


  • フレックスアイテムは使用可能なスペースを埋めるように拡大したり、オーバーフローを避けるために縮小します。このようにして、新しいコンテンツのオーバーフローの問題を解決し、また、レイアウトを整列させてレイアウトを作成した人の期待に従います。
  • フレックスアイテムに比例な寸法を与える。
  • フレックスコンテナ内のフレックスアイテムはどのようなの方向に配置することができるため、異なるメディアクエリでのコンテンツオーダーの問題を解決します。コンテンツの順序をHTMLのマークアップの順序とは無関係にすることで、サイトのレスポンシブなテーマの対応を支援します。



  • マインアクシス、メインディメンション (図ではMain axis, main dimesnsion) - フレックスコンテナの主軸は、フレックスアイテムが配置される主軸です。メインアクシスはメインディメンションの方向に伸びます。
  • メインスタート、メインエンド (図ではMain-start, main-end) - フレックスアイテムは、メインスタート側からメインエンド側に向かってコンテナ内に配置されます。
  • メインサイズ、メインサイズプロパティ (図ではMain size, main size property) - フレックスアイテムの幅または高さのいずれかがメインディメンションのものが、アイテムのメインサイズです。フレックスアイテムのメインサイズプロパティは、幅または高さプロパティのいずれかがメインディメンションになっているものになります。
  • Cross axis, cross dimension - The axis perpendicular to the main axis is called the cross axis. It extends in the cross dimension.
  • Cross-Start, cross-end - Flex lines are filled with items and placed into the container starting on the cross-start side of the flex container and going toward the cross-end side.
  • Cross size, cross size property - The width or height of a flex item, whichever is in the cross dimension, is the item’s cross size. The cross size property is whichever of width or height that is in the cross dimension.

Flex Container properties

Flex items properties

Flexbox Mixins

This is a set of mixins for those who want to mess around with flexbox using the native support of current browsers. For full support table

check: http://caniuse.com/flexbox

This will use:

  • Fallbacks using 2009 'box' syntax (FF and Older Wekbit ) and prefixed syntaxes (IE10, WebKit browsers without flex wrapping)
  • Final standards syntax (FF, Safari, Chrome, IE11, Opera)

This was inspired by:

With help from:

Note: Mixins are not currently supported natively in browsers. Instead, you will need to use a CSS pre-processor to make the most of the following. However, CSS pre-processors simply generate valid CSS, so the techniques used below can be written in pure CSS instead, if preferred.

Flexbox Containers

The 'flex' value causes an element to generate a block-level flex container box.

The 'inline-flex' value causes an element to generate an inline-level flex container box.

display: flex | inline-flex http://w3.org/tr/css3-flexbox/#flex-containers

@mixin flexbox {
  display: -webkit-box;
  display: -moz-box;
  display: -webkit-flex;
  display: -ms-flexbox;
  display: flex;

//Using this mixin
%flexbox { @include flexbox; }
@mixin inline-flex {
  display: -webkit-inline-box;
  display: -moz-inline-box;
  display: -webkit-inline-flex;
  display: -ms-inline-flexbox;
  display: inline-flex;

%inline-flex { @include inline-flex; }

Flexbox Direction

The 'flex-direction' property specifies how flex items are placed in the flex container, by setting the direction of the flex container's main axis. This determines the direction in which flex items are laid out in.

Values: row | row-reverse | column | column-reverse http://w3.org/tr/css3-flexbox/#flex-direction-property

@mixin flex-direction($value: row) {
  @if $value == row-reverse {
    -webkit-box-direction: reverse;
    -webkit-box-orient: horizontal;
    -moz-box-direction: reverse;
    -moz-box-orient: horizontal;
  } @else if $value == column {
    -webkit-box-direction: normal;
    -webkit-box-orient: vertical;
    -moz-box-direction: normal;
    -moz-box-orient: vertical;
  } @else if $value == column-reverse {
    -webkit-box-direction: reverse;
    -webkit-box-orient: vertical;
    -moz-box-direction: reverse;
    -moz-box-orient: vertical;
  } @else {
    -webkit-box-direction: normal;
    -webkit-box-orient: horizontal;
    -moz-box-direction: normal;
    -moz-box-orient: horizontal;
  -webkit-flex-direction: $value;
  -ms-flex-direction: $value;
  flex-direction: $value;

// Shorter version:
@mixin flex-dir($args...) { @include flex-direction($args...); }

Flexbox Wrap

The 'flex-wrap' property controls whether the flex container is single-lined or multi-lined, and the direction of the cross-axis, which determines the direction in which the new lines are stacked in.

Values: nowrap | wrap | wrap-reverse Default: nowrap


@mixin flex-wrap($value: nowrap) {
  // No Webkit/FF Box fallback.
  -webkit-flex-wrap: $value;
  @if $value == nowrap {
    -ms-flex-wrap: none;
  } @else {
    -ms-flex-wrap: $value;
  flex-wrap: $value;

Flexbox Flow (shorthand)

The 'flex-flow' property is shorthand for setting the 'flex-direction' and 'flex-wrap' properties, which together define the flex container's main and cross axes.

Values: | Default: row nowrap


@mixin flex-flow($values: (row nowrap)) {
  // No Webkit/FF Box fallback.
  -webkit-flex-flow: $values;
  -ms-flex-flow: $values;
  flex-flow: $values;

Flexbox Order

The 'order' property controls the order in which flex items appear within their flex container, by assigning them to ordinal groups.

Default: 0


@mixin order($int: 0) {
  -webkit-box-ordinal-group: $int + 1;
  -moz-box-ordinal-group: $int + 1;
  -webkit-order: $int;
  -ms-flex-order: $int;
  order: $int;

Flexbox Grow

The 'flex-grow' property sets the flex grow factor. Negative numbers are invalid.

Default: 1


@mixin flex-grow($int: 1) {
  -webkit-box-flex: $int;
  -moz-box-flex: $int;
  -webkit-flex-grow: $int;
  -ms-flex: $int;
  flex-grow: $int;

Flexbox Shrink

The 'flex-shrink' property sets the flex shrink factor. Negative numbers are invalid.

Default: 0


@mixin flex-shrink($int: 0) {
  -webkit-flex-shrink: 1 $int;
  -moz-flex-shrink: 1 $int;
  -ms-flex: 1 $int;
  flex-shrink: 1 $int;

Flexbox Basis

The 'flex-basis' property sets the flex basis. Negative lengths are invalid.

Values: Like "width" Default: auto


@mixin flex-basis($value: auto) {
  -webkit-flex-basis: $value;
  flex-basis: $value;

Flexbox "Flex" (shorthand)

The 'flex' property specifies the components of a flexible length; flex grow factor, flex shrink factor, and the flex basis. When an element is a flex item, 'flex' is consulted instead of the main size property to determine the main size of the element. If an element is not a flex item, 'flex' has no effect.

Values: none | ||

Default: See individual properties (1 0 auto).


@mixin flex($fg: 1, $fs: 0, $fb: auto) {

  // Set a variable to be used by box-flex properties
  $fg-boxflex: $fg;

  // Box-Flex only supports a flex-grow value so lets grab the
  // first item in the list and just return that.
  @if type-of($fg) == 'list' {
    $fg-boxflex: nth($fg, 1);

  -webkit-box: $fg-boxflex;
  -moz-box: $fg-boxflex;
  -webkit-flex: $fg $fs $fb;
  -ms-flexbox: $fg $fs $fb;
  flex: $fg $fs $fb;

Flexbox Justify Content

The 'justify-content' property aligns flex items along the main axis of the current line of the flex container. This is done after any flexible lengths and any auto margins have been resolved. Typically, it helps to 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.

Note: 'space-*' values not supported in older syntaxes.

Values: flex-start | flex-end | center | space-between | space-around Default: flex-start


@mixin justify-content($value: flex-start) {
  @if $value == flex-start {
    -webkit-box-pack: start;
    -moz-box-pack: start;
    -ms-flex-pack: start;
  } @else if $value == flex-end {
    -webkit-box-pack: end;
    -moz-box-pack: end;
    -ms-flex-pack: end;
  } @else if $value == space-between {
    -webkit-box-pack: justify;
    -moz-box-pack: justify;
    -ms-flex-pack: justify;
  } @else if $value == space-around {
    -ms-flex-pack: distribute;
  } @else {
    -webkit-box-pack: $value;
    -moz-box-pack: $value;
    -ms-flex-pack: $value;
  -webkit-justify-content: $value;
  justify-content: $value;
  // Shorter version:
  @mixin flex-just($args...) { @include justify-content($args...); }

Flexbox Align Items

Flex items can be aligned in the cross axis of the current line of the flex container, similar to 'justify-content' but in the perpendicular direction. 'align-items' sets the default alignment for all of the flex container's items, including anonymous flex items. 'align-self' allows this default alignment to be overridden for individual flex items. (For anonymous flex items, 'align-self' always matches the value of 'align-items' on their associated flex container.)

Values: flex-start | flex-end | center | baseline | stretch Default: stretch


@mixin align-items($value: stretch) {
  @if $value == flex-start {
    -webkit-box-align: start;
    -moz-box-align: start;
    -ms-flex-align: start;
  } @else if $value == flex-end {
    -webkit-box-align: end;
    -moz-box-align: end;
    -ms-flex-align: end;
  } @else {
    -webkit-box-align: $value;
    -moz-box-align: $value;
    -ms-flex-align: $value;
  -webkit-align-items: $value;
  align-items: $value;

Flexbox Align Self

Values: auto | flex-start | flex-end | center | baseline | stretch Default: auto

@mixin align-self($value: auto) {
  // No Webkit Box Fallback.
  -webkit-align-self: $value;
  @if $value == flex-start {
    -ms-flex-item-align: start;
  } @else if $value == flex-end {
    -ms-flex-item-align: end;
  } @else {
    -ms-flex-item-align: $value;
  align-self: $value;

Flexbox Align Content

The 'align-content' property aligns a flex container's lines within the flex container when there is extra space in the cross-axis, similar to how 'justify-content' aligns individual items within the main-axis. Note, this property has no effect when the flexbox has only a single line.

Values: flex-start | flex-end | center | space-between | space-around | stretch Default: stretch


@mixin align-content($value: stretch) {
  // No Webkit Box Fallback.
  -webkit-align-content: $value;
  @if $value == flex-start {
    -ms-flex-line-pack: start;
  } @else if $value == flex-end {
    -ms-flex-line-pack: end;
  } @else {
    -ms-flex-line-pack: $value;
  align-content: $value;


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 最終更新者: chrisdavidmills,