Source

Spacing

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

How it works

Assign responsive-friendly marginor paddingvalues 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 .25remto 3rem.

notation

Spacing utilities that apply to all breakpoints, from xsto xl, have no breakpoint abbreviation in them. This is because those classes are applied from min-width: 0and 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 xsand {property}{sides}-{breakpoint}-{size}for sm, md, lg, and xl.

Where property is one of:

m- for classes that setmargin
p- for classes that setpadding

Where sides is one of:

t- for classes that set margin-toporpadding-top
b- for classes that set margin-bottomorpadding-bottom
l- for classes that set margin-leftorpadding-left
r- for classes that set margin-rightorpadding-right
x- for classes that set both *-leftand*-right
y- for classes that set both *-topand*-bottom
blank - for classes that set a marginor paddingon all 4 sides of the element

Where size is one of:

0- for classes that eliminate the marginor paddingby setting it to0
1- (by default) for classes that set the marginor paddingto$spacer * .25
2- (by default) for classes that set the marginor paddingto$spacer * .5
3- (by default) for classes that set the marginor paddingto$spacer
4- (by default) for classes that set the marginor paddingto$spacer * 1.5
5- (by default) for classes that set the marginor paddingto$spacer * 3
auto- for classes that set the marginto auto

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

Examples

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;
}

horizontal centering

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

centered element

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

negative margin

In CSS, marginproperties can utilize negative values ( paddingcannot). As of 4.2, we've added negative margin utilities for every non-zero integer size listed above (eg, 1, 2, 3, 4, 5). These utilities are ideal for customizing grid column gutters across breakpoints.

The syntax is nearly the same as the default, positive margin utilities, but with the addition of nbefore the requested size. Here's an example class that's the opposite of .mt-1:

.mt-n1 {
  margin-top: -0.25rem !important;
}

Here's an example of customizing the Bootstrap grid at the medium ( md) breakpoint and above. We've increased the .colpadding with .px-md-5and then counteracted that with .mx-md-n5on the parent .row.

custom column padding

<div class="row mx-md-n5">
  <div class="col px-md-5"><div class="p-3 border bg-light">Custom column padding</div></div>
  <div class="col px-md-5"><div class="p-3 border bg-light">Custom column padding</div></div>
</div>