欄 (Columns)
借助我們的 flexbox 網格系統，瞭解如何透過一些選項來修改欄的對齊、排序以及偏移。另外，請參閱如何使用欄位類別管理非網格系統元素的寬度。
如何運作
-
Columns 的網格主要建立於 flexbox 上。 Flexbox 意味著我們可以選擇更改單個 columns 以及 在 row 級別修改 column 群組。 您可以選擇 columns 的增長、收縮或其他更改方式。
-
建立網格排版時，所有內容都是在 Columns 中。 Bootstrap 網格的層次結構從 container 到您的 row、column、content。在極少數情況下，您可以將內容與 column 結合，但要注意可能會產生意想不到的後果。
-
Bootstrap 包含用於快速建立，響應式排版的預定義 class。 借助六個斷點以及每個網格層的十二欄，我們已建構了數十個種類來創建所需要的排版。如果您願意，可以透過 Sass 禁用他。
對齊
使用 flexbox 對齊垂直和水平。
垂直對齊
<div class="container">
<div class="row align-items-start">
<div class="col">
One of three columns
</div>
<div class="col">
One of three columns
</div>
<div class="col">
One of three columns
</div>
</div>
<div class="row align-items-center">
<div class="col">
One of three columns
</div>
<div class="col">
One of three columns
</div>
<div class="col">
One of three columns
</div>
</div>
<div class="row align-items-end">
<div class="col">
One of three columns
</div>
<div class="col">
One of three columns
</div>
<div class="col">
One of three columns
</div>
</div>
</div><div class="container">
<div class="row">
<div class="col align-self-start">
One of three columns
</div>
<div class="col align-self-center">
One of three columns
</div>
<div class="col align-self-end">
One of three columns
</div>
</div>
</div>水平對齊
<div class="container">
<div class="row justify-content-start">
<div class="col-4">
One of two columns
</div>
<div class="col-4">
One of two columns
</div>
</div>
<div class="row justify-content-center">
<div class="col-4">
One of two columns
</div>
<div class="col-4">
One of two columns
</div>
</div>
<div class="row justify-content-end">
<div class="col-4">
One of two columns
</div>
<div class="col-4">
One of two columns
</div>
</div>
<div class="row justify-content-around">
<div class="col-4">
One of two columns
</div>
<div class="col-4">
One of two columns
</div>
</div>
<div class="row justify-content-between">
<div class="col-4">
One of two columns
</div>
<div class="col-4">
One of two columns
</div>
</div>
<div class="row justify-content-evenly">
<div class="col-4">
One of two columns
</div>
<div class="col-4">
One of two columns
</div>
</div>
</div>欄的換行
如果 12 個以上的欄位於單獨一行內，每一組額外欄（作為一個單元）將換新的一行。
Since 9 + 4 = 13 > 12, this 4-column-wide div gets wrapped onto a new line as one contiguous unit.
Subsequent columns continue along the new line.
<div class="container">
<div class="row">
<div class="col-9">.col-9</div>
<div class="col-4">.col-4<br>Since 9 + 4 = 13 > 12, this 4-column-wide div gets wrapped onto a new line as one contiguous unit.</div>
<div class="col-6">.col-6<br>Subsequent columns continue along the new line.</div>
</div>
</div>Column breaks
在 Flexbox 中將列拆分成新行需要一個小 hack : 當你想中斷你的欄到新的一行，可增加一個元素為 width: 100%。正常來說，通常這是通過多個 .row 完成的，但此方法也是可行的。
<div class="container">
<div class="row">
<div class="col-6 col-sm-3">.col-6 .col-sm-3</div>
<div class="col-6 col-sm-3">.col-6 .col-sm-3</div>
<!-- Force next columns to break to new line -->
<div class="w-100"></div>
<div class="col-6 col-sm-3">.col-6 .col-sm-3</div>
<div class="col-6 col-sm-3">.col-6 .col-sm-3</div>
</div>
</div>你也可以採用響應式的 display 通用類別 來達成這種效果。
<div class="container">
<div class="row">
<div class="col-6 col-sm-4">.col-6 .col-sm-4</div>
<div class="col-6 col-sm-4">.col-6 .col-sm-4</div>
<!-- Force next columns to break to new line at md breakpoint and up -->
<div class="w-100 d-none d-md-block"></div>
<div class="col-6 col-sm-4">.col-6 .col-sm-4</div>
<div class="col-6 col-sm-4">.col-6 .col-sm-4</div>
</div>
</div>排序
Order classes
使用 .order-class 來控制內容中 可見的內容 順序，這些 class 是響應式的，所以可以設定 order 在不同斷點上 (e.g., .order-1.order-md-2)，包含支援 1 ~ 5 及不同的中斷點。
<div class="container">
<div class="row">
<div class="col">
First in DOM, no order applied
</div>
<div class="col order-5">
Second in DOM, with a larger order
</div>
<div class="col order-1">
Third in DOM, with an order of 1
</div>
</div>
</div>還有一個響應式的 .order-first 和 .order-last，可以透過 order: -1 和 order: 6 來快速更改一個元素的順序。 這個 Class 也可以依據需要與編號的 .order-* 混合使用。
<div class="container">
<div class="row">
<div class="col order-last">
First in DOM, ordered last
</div>
<div class="col">
Second in DOM, unordered
</div>
<div class="col order-first">
Third in DOM, ordered first
</div>
</div>
</div>欄的推移
您可以通過兩種方式來位移欄 .offset- Class 和 margin 通用類別。網格位移的空間與欄間格相符合，這種推移對於快速排版可增加更多變化。
位移類別
使用 .offset-md-* 向右移動列。 透過 * 增加欄的左邊距。 例如 .offset-md-4 增加四欄位移 .col-md-4。
<div class="container">
<div class="row">
<div class="col-md-4">.col-md-4</div>
<div class="col-md-4 offset-md-4">.col-md-4 .offset-md-4</div>
</div>
<div class="row">
<div class="col-md-3 offset-md-3">.col-md-3 .offset-md-3</div>
<div class="col-md-3 offset-md-3">.col-md-3 .offset-md-3</div>
</div>
<div class="row">
<div class="col-md-6 offset-md-3">.col-md-6 .offset-md-3</div>
</div>
</div>除了增加在欄的位移，您也可以透過中斷點重置位移量。在 網格範例 中查看此操作。
<div class="container">
<div class="row">
<div class="col-sm-5 col-md-6">.col-sm-5 .col-md-6</div>
<div class="col-sm-5 offset-sm-2 col-md-6 offset-md-0">.col-sm-5 .offset-sm-2 .col-md-6 .offset-md-0</div>
</div>
<div class="row">
<div class="col-sm-6 col-md-5 col-lg-6">.col-sm-6 .col-md-5 .col-lg-6</div>
<div class="col-sm-6 col-md-5 offset-md-2 col-lg-6 offset-lg-0">.col-sm-6 .col-md-5 .offset-md-2 .col-lg-6 .offset-lg-0</div>
</div>
</div>Margin 通用類別
隨著第四版改用 flexbox，你可以透過 margin 的通用類別，像是 .me-auto 將相鄰的欄位分離到另一邊。
<div class="container">
<div class="row">
<div class="col-md-4">.col-md-4</div>
<div class="col-md-4 ms-auto">.col-md-4 .ms-auto</div>
</div>
<div class="row">
<div class="col-md-3 ms-md-auto">.col-md-3 .ms-md-auto</div>
<div class="col-md-3 ms-md-auto">.col-md-3 .ms-md-auto</div>
</div>
<div class="row">
<div class="col-auto me-auto">.col-auto .me-auto</div>
<div class="col-auto">.col-auto</div>
</div>
</div>獨立 Column class
.col-* 也可以在 .row 之外使用，用於給予元素特定的寬度。當 Column 不用於 Row 以下時，都會直接填滿。
<div class="col-3 bg-light p-3 border">
.col-3: width of 25%
</div>
<div class="col-sm-9 bg-light p-3 border">
.col-sm-9: width of 75% above sm breakpoint
</div>這些 class 可以與通用類別一起使用，以建立一個響應式的浮動元素圖片。請確保內容是包覆在 .clearfix 內，以確保內容較短時清除浮動元素。
A paragraph of placeholder text. We're using it here to show the use of the clearfix class. We're adding quite a few meaningless phrases here to demonstrate how the columns interact here with the floated image.
As you can see the paragraphs gracefully wrap around the floated image. Now imagine how this would look with some actual content in here, rather than just this boring placeholder text that goes on and on, but actually conveys no tangible information at. It simply takes up space and should not really be read.
And yet, here you are, still persevering in reading this placeholder text, hoping for some more insights, or some hidden easter egg of content. A joke, perhaps. Unfortunately, there's none of that here.
<div class="clearfix">
<img src="..." class="col-md-6 float-md-end mb-3 ms-md-3" alt="...">
<p>
A paragraph of placeholder text. We're using it here to show the use of the clearfix class. We're adding quite a few meaningless phrases here to demonstrate how the columns interact here with the floated image.
</p>
<p>
As you can see the paragraphs gracefully wrap around the floated image. Now imagine how this would look with some actual content in here, rather than just this boring placeholder text that goes on and on, but actually conveys no tangible information at. It simply takes up space and should not really be read.
</p>
<p>
And yet, here you are, still persevering in reading this placeholder text, hoping for some more insights, or some hidden easter egg of content. A joke, perhaps. Unfortunately, there's none of that here.
</p>
</div>