弹性

启用弹性行为

¥Enable flex behaviors

应用 display 工具创建 Flexbox 容器并将直接子元素转换为 Flex 项目。Flex 容器和项目可以通过附加的 flex 属性进行进一步修改。

¥Apply display utilities to create a flexbox container and transform direct children elements into flex items. Flex containers and items are able to be modified further with additional flex properties.

<div class="d-flex p-2">I'm a flexbox container!</div>

<div class="d-inline-flex p-2">I'm an inline flexbox container!</div>

.d-flex 和 .d-inline-flex 也存在响应变化。

¥Responsive variations also exist for .d-flex and .d-inline-flex.

• .d-flex
• .d-inline-flex
• .d-sm-flex
• .d-sm-inline-flex
• .d-md-flex
• .d-md-inline-flex
• .d-lg-flex
• .d-lg-inline-flex
• .d-xl-flex
• .d-xl-inline-flex
• .d-xxl-flex
• .d-xxl-inline-flex

方向

¥Direction

使用方向工具设置 Flex 容器中 Flex 项目的方向。在大多数情况下，你可以在此处省略水平类，因为浏览器默认值为 row。但是，你可能会遇到需要显式设置此值的情况（例如响应式布局）。

¥Set the direction of flex items in a flex container with direction utilities. In most cases you can omit the horizontal class here as the browser default is row. However, you may encounter situations where you needed to explicitly set this value (like responsive layouts).

使用 .flex-row 设置水平方向（浏览器默认），或使用 .flex-row-reverse 从相反一侧开始水平方向。

¥Use .flex-row to set a horizontal direction (the browser default), or .flex-row-reverse to start the horizontal direction from the opposite side.

<div class="d-flex flex-row mb-3">
  <div class="p-2">Flex item 1</div>
  <div class="p-2">Flex item 2</div>
  <div class="p-2">Flex item 3</div>
</div>
<div class="d-flex flex-row-reverse">
  <div class="p-2">Flex item 1</div>
  <div class="p-2">Flex item 2</div>
  <div class="p-2">Flex item 3</div>
</div>

使用 .flex-column 设置垂直方向，或使用 .flex-column-reverse 从相反一侧开始垂直方向。

¥Use .flex-column to set a vertical direction, or .flex-column-reverse to start the vertical direction from the opposite side.

<div class="d-flex flex-column mb-3">
  <div class="p-2">Flex item 1</div>
  <div class="p-2">Flex item 2</div>
  <div class="p-2">Flex item 3</div>
</div>
<div class="d-flex flex-column-reverse">
  <div class="p-2">Flex item 1</div>
  <div class="p-2">Flex item 2</div>
  <div class="p-2">Flex item 3</div>
</div>

flex-direction 也存在响应变化。

¥Responsive variations also exist for flex-direction.

• .flex-row
• .flex-row-reverse
• .flex-column
• .flex-column-reverse
• .flex-sm-row
• .flex-sm-row-reverse
• .flex-sm-column
• .flex-sm-column-reverse
• .flex-md-row
• .flex-md-row-reverse
• .flex-md-column
• .flex-md-column-reverse
• .flex-lg-row
• .flex-lg-row-reverse
• .flex-lg-column
• .flex-lg-column-reverse
• .flex-xl-row
• .flex-xl-row-reverse
• .flex-xl-column
• .flex-xl-column-reverse
• .flex-xxl-row
• .flex-xxl-row-reverse
• .flex-xxl-column
• .flex-xxl-column-reverse

证明内容合理

¥Justify content

在 Flexbox 容器上使用 justify-content 工具来更改 Flex 项目在主轴上的对齐方式（从 x 轴开始，如果是 flex-direction: column，则从 y 轴）。从 start（浏览器默认值）、end、center、between、around 或 evenly 中进行选择。

¥Use justify-content utilities on flexbox containers to change the alignment of flex items on the main axis (the x-axis to start, y-axis if flex-direction: column). Choose from start (browser default), end, center, between, around, or evenly.

<div class="d-flex justify-content-start">...</div>
<div class="d-flex justify-content-end">...</div>
<div class="d-flex justify-content-center">...</div>
<div class="d-flex justify-content-between">...</div>
<div class="d-flex justify-content-around">...</div>
<div class="d-flex justify-content-evenly">...</div>

justify-content 也存在响应变化。

¥Responsive variations also exist for justify-content.

• .justify-content-start
• .justify-content-end
• .justify-content-center
• .justify-content-between
• .justify-content-around
• .justify-content-evenly
• .justify-content-sm-start
• .justify-content-sm-end
• .justify-content-sm-center
• .justify-content-sm-between
• .justify-content-sm-around
• .justify-content-sm-evenly
• .justify-content-md-start
• .justify-content-md-end
• .justify-content-md-center
• .justify-content-md-between
• .justify-content-md-around
• .justify-content-md-evenly
• .justify-content-lg-start
• .justify-content-lg-end
• .justify-content-lg-center
• .justify-content-lg-between
• .justify-content-lg-around
• .justify-content-lg-evenly
• .justify-content-xl-start
• .justify-content-xl-end
• .justify-content-xl-center
• .justify-content-xl-between
• .justify-content-xl-around
• .justify-content-xl-evenly
• .justify-content-xxl-start
• .justify-content-xxl-end
• .justify-content-xxl-center
• .justify-content-xxl-between
• .justify-content-xxl-around
• .justify-content-xxl-evenly

对齐项目

¥Align items

在 Flexbox 容器上使用 align-items 工具来更改横轴上 Flex 项目的对齐方式（从 y 轴开始，如果是 flex-direction: column，则从 x 轴）。从 start、end、center、baseline 或 stretch（浏览器默认值）中进行选择。

¥Use align-items utilities on flexbox containers to change the alignment of flex items on the cross axis (the y-axis to start, x-axis if flex-direction: column). Choose from start, end, center, baseline, or stretch (browser default).

<div class="d-flex align-items-start">...</div>
<div class="d-flex align-items-end">...</div>
<div class="d-flex align-items-center">...</div>
<div class="d-flex align-items-baseline">...</div>
<div class="d-flex align-items-stretch">...</div>

align-items 也存在响应变化。

¥Responsive variations also exist for align-items.

• .align-items-start
• .align-items-end
• .align-items-center
• .align-items-baseline
• .align-items-stretch
• .align-items-sm-start
• .align-items-sm-end
• .align-items-sm-center
• .align-items-sm-baseline
• .align-items-sm-stretch
• .align-items-md-start
• .align-items-md-end
• .align-items-md-center
• .align-items-md-baseline
• .align-items-md-stretch
• .align-items-lg-start
• .align-items-lg-end
• .align-items-lg-center
• .align-items-lg-baseline
• .align-items-lg-stretch
• .align-items-xl-start
• .align-items-xl-end
• .align-items-xl-center
• .align-items-xl-baseline
• .align-items-xl-stretch
• .align-items-xxl-start
• .align-items-xxl-end
• .align-items-xxl-center
• .align-items-xxl-baseline
• .align-items-xxl-stretch

对齐自身

¥Align self

在 Flexbox 项目上使用 align-self 工具来单独更改其在横轴上的对齐方式（从 y 轴开始，如果是 flex-direction: column，则从 x 轴）。从与 align-items 相同的选项中进行选择：start、end、center、baseline 或 stretch（浏览器默认值）。

¥Use align-self utilities on flexbox items to individually change their alignment on the cross axis (the y-axis to start, x-axis if flex-direction: column). Choose from the same options as align-items: start, end, center, baseline, or stretch (browser default).

<div class="align-self-start">Aligned flex item</div>
<div class="align-self-end">Aligned flex item</div>
<div class="align-self-center">Aligned flex item</div>
<div class="align-self-baseline">Aligned flex item</div>
<div class="align-self-stretch">Aligned flex item</div>

align-self 也存在响应变化。

¥Responsive variations also exist for align-self.

• .align-self-start
• .align-self-end
• .align-self-center
• .align-self-baseline
• .align-self-stretch
• .align-self-sm-start
• .align-self-sm-end
• .align-self-sm-center
• .align-self-sm-baseline
• .align-self-sm-stretch
• .align-self-md-start
• .align-self-md-end
• .align-self-md-center
• .align-self-md-baseline
• .align-self-md-stretch
• .align-self-lg-start
• .align-self-lg-end
• .align-self-lg-center
• .align-self-lg-baseline
• .align-self-lg-stretch
• .align-self-xl-start
• .align-self-xl-end
• .align-self-xl-center
• .align-self-xl-baseline
• .align-self-xl-stretch
• .align-self-xxl-start
• .align-self-xxl-end
• .align-self-xxl-center
• .align-self-xxl-baseline
• .align-self-xxl-stretch

充满

¥Fill

在一系列同级元素上使用 .flex-fill 类，强制它们的宽度等于其内容（或者，如果它们的内容不超过其边框框，则宽度相等），同时占用所有可用的水平空间。

¥Use the .flex-fill class on a series of sibling elements to force them into widths equal to their content (or equal widths if their content does not surpass their border-boxes) while taking up all available horizontal space.

<div class="d-flex">
  <div class="p-2 flex-fill">Flex item with a lot of content</div>
  <div class="p-2 flex-fill">Flex item</div>
  <div class="p-2 flex-fill">Flex item</div>
</div>

flex-fill 也存在响应变化。

¥Responsive variations also exist for flex-fill.

• .flex-fill
• .flex-sm-fill
• .flex-md-fill
• .flex-lg-fill
• .flex-xl-fill
• .flex-xxl-fill

增长和收缩

¥Grow and shrink

使用 .flex-grow-* 工具来切换弹性项目的增长以填充可用空间的能力。在下面的示例中，.flex-grow-1 元素使用了所有可用空间，同时允许剩余的两个 Flex 项目拥有必要的空间。

¥Use .flex-grow-* utilities to toggle a flex item’s ability to grow to fill available space. In the example below, the .flex-grow-1 elements uses all available space it can, while allowing the remaining two flex items their necessary space.

<div class="d-flex">
  <div class="p-2 flex-grow-1">Flex item</div>
  <div class="p-2">Flex item</div>
  <div class="p-2">Third flex item</div>
</div>

如有必要，使用 .flex-shrink-* 工具切换弹性项目的收缩能力。在下面的示例中，第二个带有 .flex-shrink-1 的 Flex 项目被迫将其内容换行到新行 “shrinking”，以便为前一个带有 .w-100 的 Flex 项目留出更多空间。

¥Use .flex-shrink-* utilities to toggle a flex item’s ability to shrink if necessary. In the example below, the second flex item with .flex-shrink-1 is forced to wrap its contents to a new line, “shrinking” to allow more space for the previous flex item with .w-100.

<div class="d-flex">
  <div class="p-2 w-100">Flex item</div>
  <div class="p-2 flex-shrink-1">Flex item</div>
</div>

flex-grow 和 flex-shrink 也存在响应变化。

¥Responsive variations also exist for flex-grow and flex-shrink.

• .flex-{grow|shrink}-0
• .flex-{grow|shrink}-1
• .flex-sm-{grow|shrink}-0
• .flex-sm-{grow|shrink}-1
• .flex-md-{grow|shrink}-0
• .flex-md-{grow|shrink}-1
• .flex-lg-{grow|shrink}-0
• .flex-lg-{grow|shrink}-1
• .flex-xl-{grow|shrink}-0
• .flex-xl-{grow|shrink}-1
• .flex-xxl-{grow|shrink}-0
• .flex-xxl-{grow|shrink}-1

自动边距

¥Auto margins

当你将弹性对齐与自动边距混合时，Flexbox 可以做一些非常棒的事情。下面显示了通过自动边距控制弹性项目的三个示例：默认（无自动边距），将两个项目向右推 (.me-auto)，并将两个项目向左推 (.ms-auto)。

¥Flexbox can do some pretty awesome things when you mix flex alignments with auto margins. Shown below are three examples of controlling flex items via auto margins: default (no auto margin), pushing two items to the right (.me-auto), and pushing two items to the left (.ms-auto).

<div class="d-flex mb-3">
  <div class="p-2">Flex item</div>
  <div class="p-2">Flex item</div>
  <div class="p-2">Flex item</div>
</div>

<div class="d-flex mb-3">
  <div class="me-auto p-2">Flex item</div>
  <div class="p-2">Flex item</div>
  <div class="p-2">Flex item</div>
</div>

<div class="d-flex mb-3">
  <div class="p-2">Flex item</div>
  <div class="p-2">Flex item</div>
  <div class="ms-auto p-2">Flex item</div>
</div>

使用对齐项目

¥With align-items

通过混合 align-items、flex-direction: column 和 margin-top: auto 或 margin-bottom: auto，将一个弹性项目垂直移动到容器的顶部或底部。

¥Vertically move one flex item to the top or bottom of a container by mixing align-items, flex-direction: column, and margin-top: auto or margin-bottom: auto.

<div class="d-flex align-items-start flex-column mb-3" style="height: 200px;">
  <div class="mb-auto p-2">Flex item</div>
  <div class="p-2">Flex item</div>
  <div class="p-2">Flex item</div>
</div>

<div class="d-flex align-items-end flex-column mb-3" style="height: 200px;">
  <div class="p-2">Flex item</div>
  <div class="p-2">Flex item</div>
  <div class="mt-auto p-2">Flex item</div>
</div>

封装

¥Wrap

更改 Flex 项目在 Flex 容器中的封装方式。选择使用 .flex-nowrap 完全不换行（浏览器默认）、使用 .flex-wrap 换行或使用 .flex-wrap-reverse 反向换行。

¥Change how flex items wrap in a flex container. Choose from no wrapping at all (the browser default) with .flex-nowrap, wrapping with .flex-wrap, or reverse wrapping with .flex-wrap-reverse.

<div class="d-flex flex-nowrap">
  ...
</div>

<div class="d-flex flex-wrap">
  ...
</div>

<div class="d-flex flex-wrap-reverse">
  ...
</div>

flex-wrap 也存在响应变化。

¥Responsive variations also exist for flex-wrap.

• .flex-nowrap
• .flex-wrap
• .flex-wrap-reverse
• .flex-sm-nowrap
• .flex-sm-wrap
• .flex-sm-wrap-reverse
• .flex-md-nowrap
• .flex-md-wrap
• .flex-md-wrap-reverse
• .flex-lg-nowrap
• .flex-lg-wrap
• .flex-lg-wrap-reverse
• .flex-xl-nowrap
• .flex-xl-wrap
• .flex-xl-wrap-reverse
• .flex-xxl-nowrap
• .flex-xxl-wrap
• .flex-xxl-wrap-reverse

命令

¥Order

使用一些 order 工具更改特定弹性项目的视觉顺序。我们只提供将项目放在第一个或最后一个的选项，以及重置以使用 DOM 顺序。由于 order 采用 0 到 5 之间的任何整数值，因此请为所需的任何其他值添加自定义 CSS。

¥Change the visual order of specific flex items with a handful of order utilities. We only provide options for making an item first or last, as well as a reset to use the DOM order. As order takes any integer value from 0 to 5, add custom CSS for any additional values needed.

<div class="d-flex flex-nowrap">
  <div class="order-3 p-2">First flex item</div>
  <div class="order-2 p-2">Second flex item</div>
  <div class="order-1 p-2">Third flex item</div>
</div>

order 也存在响应变化。

¥Responsive variations also exist for order.

• .order-0
• .order-1
• .order-2
• .order-3
• .order-4
• .order-5
• .order-sm-0
• .order-sm-1
• .order-sm-2
• .order-sm-3
• .order-sm-4
• .order-sm-5
• .order-md-0
• .order-md-1
• .order-md-2
• .order-md-3
• .order-md-4
• .order-md-5
• .order-lg-0
• .order-lg-1
• .order-lg-2
• .order-lg-3
• .order-lg-4
• .order-lg-5
• .order-xl-0
• .order-xl-1
• .order-xl-2
• .order-xl-3
• .order-xl-4
• .order-xl-5
• .order-xxl-0
• .order-xxl-1
• .order-xxl-2
• .order-xxl-3
• .order-xxl-4
• .order-xxl-5

此外，还有响应式 .order-first 和 .order-last 类，它们分别通过应用 order: -1 和 order: 6 来更改元素的 order。

¥Additionally there are also responsive .order-first and .order-last classes that change the order of an element by applying order: -1 and order: 6, respectively.

• .order-first
• .order-last
• .order-sm-first
• .order-sm-last
• .order-md-first
• .order-md-last
• .order-lg-first
• .order-lg-last
• .order-xl-first
• .order-xl-last
• .order-xxl-first
• .order-xxl-last

对齐内容

¥Align content

在 Flexbox 容器上使用 align-content 工具将 Flex 项目在横轴上对齐。从 start（浏览器默认值）、end、center、between、around 或 stretch 中进行选择。为了演示这些工具，我们强制实现了 flex-wrap: wrap 并增加了弹性项目的数量。

¥Use align-content utilities on flexbox containers to align flex items together on the cross axis. Choose from start (browser default), end, center, between, around, or stretch. To demonstrate these utilities, we’ve enforced flex-wrap: wrap and increased the number of flex items.

小心！此属性对单行弹性项目没有影响。

¥Heads up! This property has no effect on single rows of flex items.

<div class="d-flex align-content-start flex-wrap">
  ...
</div>

<div class="d-flex align-content-end flex-wrap">...</div>

<div class="d-flex align-content-center flex-wrap">...</div>

<div class="d-flex align-content-between flex-wrap">...</div>

<div class="d-flex align-content-around flex-wrap">...</div>

<div class="d-flex align-content-stretch flex-wrap">...</div>

align-content 也存在响应变化。

¥Responsive variations also exist for align-content.

• .align-content-start
• .align-content-end
• .align-content-center
• .align-content-between
• .align-content-around
• .align-content-stretch
• .align-content-sm-start
• .align-content-sm-end
• .align-content-sm-center
• .align-content-sm-between
• .align-content-sm-around
• .align-content-sm-stretch
• .align-content-md-start
• .align-content-md-end
• .align-content-md-center
• .align-content-md-between
• .align-content-md-around
• .align-content-md-stretch
• .align-content-lg-start
• .align-content-lg-end
• .align-content-lg-center
• .align-content-lg-between
• .align-content-lg-around
• .align-content-lg-stretch
• .align-content-xl-start
• .align-content-xl-end
• .align-content-xl-center
• .align-content-xl-between
• .align-content-xl-around
• .align-content-xl-stretch
• .align-content-xxl-start
• .align-content-xxl-end
• .align-content-xxl-center
• .align-content-xxl-between
• .align-content-xxl-around
• .align-content-xxl-stretch

媒体对象

¥Media object

想要从 Bootstrap 4 复制 媒体对象组件？使用一些 Flex 工具立即重新创建它，这些工具比以前具有更多的灵活性和定制性。

¥Looking to replicate the media object component from Bootstrap 4? Recreate it in no time with a few flex utilities that allow even more flexibility and customization than before.

<div class="d-flex">
  <div class="flex-shrink-0">
    <img src="..." alt="...">
  </div>
  <div class="flex-grow-1 ms-3">
    This is some content from a media component. You can replace this with any content and adjust it as needed.
  </div>
</div>

并假设你要将图片旁边的内容垂直居中：

¥And say you want to vertically center the content next to the image:

<div class="d-flex align-items-center">
  <div class="flex-shrink-0">
    <img src="..." alt="...">
  </div>
  <div class="flex-grow-1 ms-3">
    This is some content from a media component. You can replace this with any content and adjust it as needed.
  </div>
</div>

CSS

Sass 工具 API

¥Sass utilities API

Flexbox 工具在 scss/_utilities.scss 中的工具 API 中声明。Learn how to use the utilities API.

¥Flexbox utilities are declared in our utilities API in scss/_utilities.scss. Learn how to use the utilities API.

"flex": (
  responsive: true,
  property: flex,
  values: (fill: 1 1 auto)
),
"flex-direction": (
  responsive: true,
  property: flex-direction,
  class: flex,
  values: row column row-reverse column-reverse
),
"flex-grow": (
  responsive: true,
  property: flex-grow,
  class: flex,
  values: (
    grow-0: 0,
    grow-1: 1,
  )
),
"flex-shrink": (
  responsive: true,
  property: flex-shrink,
  class: flex,
  values: (
    shrink-0: 0,
    shrink-1: 1,
  )
),
"flex-wrap": (
  responsive: true,
  property: flex-wrap,
  class: flex,
  values: wrap nowrap wrap-reverse
),
"justify-content": (
  responsive: true,
  property: justify-content,
  values: (
    start: flex-start,
    end: flex-end,
    center: center,
    between: space-between,
    around: space-around,
    evenly: space-evenly,
  )
),
"align-items": (
  responsive: true,
  property: align-items,
  values: (
    start: flex-start,
    end: flex-end,
    center: center,
    baseline: baseline,
    stretch: stretch,
  )
),
"align-content": (
  responsive: true,
  property: align-content,
  values: (
    start: flex-start,
    end: flex-end,
    center: center,
    between: space-between,
    around: space-around,
    stretch: stretch,
  )
),
"align-self": (
  responsive: true,
  property: align-self,
  values: (
    auto: auto,
    start: flex-start,
    end: flex-end,
    center: center,
    baseline: baseline,
    stretch: stretch,
  )
),
"order": (
  responsive: true,
  property: order,
  values: (
    first: -1,
    0: 0,
    1: 1,
    2: 2,
    3: 3,
    4: 4,
    5: 5,
    last: 6,
  ),
),