余白

Bootstrap includes a wide range of shorthand responsive margin and padding utility classes to modify an element’s appearance.

仕組み

Assign responsive-friendly margin or padding values to an element or a subset of its sides with shorthand classes. Includes support for individual properties, all properties, and vertical and horizontal properties. Classes are built from a default Sass map ranging from .25rem to 3rem.

記法

Spacing utilities that apply to all breakpoints, from xs to xl, have no breakpoint abbreviation in them. This is because those classes are applied from min-width: 0 and up, and thus are not bound by a media query. The remaining breakpoints, however, do include a breakpoint abbreviation.

The classes are named using the format {property}{sides}-{size} for xs and {property}{sides}-{breakpoint}-{size} for sm, md, lg, and xl.

property は次のいずれかです。

m - margin を設定するクラス
p - padding を設定するクラス

sides は次のいずれかです。

t - margin-top または padding-top を設定するクラス
b - margin-bottom または padding-bottom を設定するクラス
l - margin-left または padding-left を設定するクラス
r - margin-right または padding-right を設定するクラス
x - *-left および *-right を設定するクラス
y - *-top および *-bottom を設定するクラス
blank - for classes that set a margin or padding on all 4 sides of the element

size は次のいずれかです。

0 - for classes that eliminate the margin or padding by setting it to 0
1 - (by default) for classes that set the margin or padding to $spacer * .25
2 - (by default) for classes that set the margin or padding to $spacer * .5
3 - (by default) for classes that set the margin or padding to $spacer
4 - (by default) for classes that set the margin or padding to $spacer * 1.5
5 - (by default) for classes that set the margin or padding to $spacer * 3
auto - for classes that set the margin to auto

(You can add more sizes by adding entries to the $spacers Sass map variable.)

サンプル

Here are some representative examples of these classes:

.mt-0 {
  margin-top: 0 !important;
}

.ml-1 {
  margin-left: ($spacer * .25) !important;
}

.px-2 {
  padding-left: ($spacer * .5) !important;
  padding-right: ($spacer * .5) !important;
}

.p-3 {
  padding: $spacer !important;
}

横位置のセンタリング

Additionally, Bootstrap also includes an .mx-auto class for horizontally centering fixed-width block level content—that is, content that has display: block and a width set—by setting the horizontal margins to auto.

Centered element

<div class="mx-auto" style="width: 200px;">
  Centered element
</div>