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 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.
Notation
Spacing utilities that apply to all breakpoints, from xs to xxl, 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, xl, and xxl.
Where property is one of:
m- for classes that setmarginp- for classes that setpadding
Where sides is one of:
t- for classes that setmargin-toporpadding-topb- for classes that setmargin-bottomorpadding-bottoml- for classes that setmargin-leftorpadding-leftr- for classes that setmargin-rightorpadding-rightx- for classes that set both*-leftand*-righty- for classes that set both*-topand*-bottom- blank - for classes that set a
marginorpaddingon all 4 sides of the element
Where size is one of:
0- for classes that eliminate themarginorpaddingby setting it to01- (by default) for classes that set themarginorpaddingto$spacer * .252- (by default) for classes that set themarginorpaddingto$spacer * .53- (by default) for classes that set themarginorpaddingto$spacer4- (by default) for classes that set themarginorpaddingto$spacer * 1.55- (by default) for classes that set themarginorpaddingto$spacer * 3auto- for classes that set themarginto auto
(You can add more sizes by adding entries to the $spacers Sass map variable.)
Horizontal centering
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.
Negative margin
In CSS, margin properties can utilize negative values (padding cannot). These negative margins are disabled by default, but can be enabled in Sass by setting $enable-negative-margins: true.
The syntax is nearly the same as the default, positive margin utilities, but with the addition of n before the requested size. Here’s an example class that’s the opposite of .mt-1:
