弹性

启用弹性行为

🌐 Enable flex behaviors

使用 display 工具创建一个弹性盒子容器，并将直接子元素转换为弹性盒子项。弹性容器和项可以通过额外的弹性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 也存在响应式变体。

🌐 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

使用方向工具在弹性容器中设置弹性项目的方向。在大多数情况下，你可以省略这里的水平类，因为浏览器默认值是 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 从相反的一侧开始水平方向。

🌐 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 从另一侧开始垂直方向。

🌐 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 也存在响应式变体。

🌐 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 工具类来更改主轴（如果是 x 轴则为横轴，如果是 flex-direction: column 则为纵轴）上的 flex 项对齐方式。可选择 start（浏览器默认）、end、center、between、around 或 evenly。

🌐 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 也存在响应式变体。

🌐 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 flex 项在交叉轴上的对齐方式（纵轴为起点，若 flex-direction: column 则为横轴）。可从 start、end、center、baseline 或 stretch（浏览器默认）中选择。

🌐 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 也存在响应式变体。

🌐 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

在弹性盒子项目上使用 align-self 工具单独更改它们在交叉轴上的对齐方式（默认是 y 轴，如果 flex-direction: column 则是 x 轴）。可选择与 align-items 相同的选项：start、end、center、baseline 或 stretch（浏览器默认）。

🌐 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 也存在响应式变体。

🌐 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

在一系列兄弟元素上使用 .flex-fill 类，将它们的宽度强制为与其内容相等（如果内容没有超过它们的边框盒，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 也存在响应式变体。

🌐 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扩展以填充可用空间的能力。在下面的示例中，.flex-grow-1 元素使用它可以使用的所有可用空间，同时允许剩下的两个弹性项目占用它们所需的空间。

🌐 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>

使用 .flex-shrink-* 工具在必要时切换 flex 项的收缩能力。在下面的示例中，第二个带有 .flex-shrink-1 的 flex 项被迫将其内容换到新行，“收缩”以为前一个带有 .w-100 的 flex 项腾出更多空间。

🌐 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 也存在响应式变化。

🌐 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结合使用时，Flexbox 可以做一些相当棒的事情。下面显示了三个通过自动边距控制弹性项目的示例：默认（没有自动边距）、将两个项目推到右侧（.me-auto）以及将两个项目推到左侧（.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，可以将一个弹性项目在容器内垂直移动到顶部或底部。

🌐 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

更改弹性容器中弹性子项的换行方式。可以选择完全不换行（浏览器默认）使用 .flex-nowrap，换行使用 .flex-wrap，或反向换行使用 .flex-wrap-reverse。

🌐 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 也存在响应式变体。

🌐 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

使用少量 order 工具更改特定弹性项目的视觉顺序。我们只提供将项目置于第一或最后的位置的选项，以及用于恢复使用 DOM 顺序的重置。由于 order 可以取 0 到 5 的任何整数值，请为需要的其他值添加自定义 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 也存在响应式变体。

🌐 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，还有响应式的 .order-first 和 .order-last 类，它们分别通过应用 order: -1 和 order: 6 来改变元素的 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

使用 align-content 工具在 flexbox 容器上使弹性子项在交叉轴上 一起 对齐。可选择 start（浏览器默认）、end、center、between、around 或 stretch。为了演示这些工具，我们已强制使用 flex-wrap: wrap 并增加了弹性子项的数量。

🌐 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.

注意！ 这个属性对单行的弹性项目没有效果。

<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 也存在响应式变体。

🌐 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

想要复制 Bootstrap 4 的 媒体对象组件 吗？只需使用几个弹性工具即可在短时间内重现它，这些工具甚至比以前提供了更多的灵活性和自定义选项。

🌐 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 实用工具在我们的实用工具 API 中声明，位于 scss/_utilities.scss。了解如何使用实用工具 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,
  ),
),