Spacing

    Assign responsive-friendly 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.

    Using the CSS Grid layout module? Consider using the gap utility.

    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 set margin
    • p - for classes that set padding
    • t - for classes that set margin-top or padding-top
    • b - for classes that set margin-bottom or padding-bottom
    • s - (start) for classes that set margin-left or padding-left in LTR, margin-right or padding-right in RTL
    • e - (end) for classes that set margin-right or padding-right in LTR, margin-left or padding-left in RTL
    • x - for classes that set both *-left and *-right
    • y - for classes that set both *-top and *-bottom
    • blank - for classes that set a margin or padding on all 4 sides of the element

    Where size is one of:

    • 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.)

    Here are some representative examples of these classes:

    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.

    1. <div class="mx-auto" style="width: 200px;">
    3. </div>

    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:

    When using display: grid, you can make use of gap utilities on the parent grid container. This can save on having to add margin utilities to individual grid items (children of a display: grid container). Gap utilities are responsive by default, and are generated via our utilities API, based on the $spacers Sass map.

    Spacing - 图2

    1. <div class="d-grid gap-3">
    2.   <div class="p-2 bg-light border">Grid item 1</div>
    3.   <div class="p-2 bg-light border">Grid item 2</div>
    4.   <div class="p-2 bg-light border">Grid item 3</div>
    5. </div>

    Support includes responsive options for all of Bootstrap’s grid breakpoints, as well as six sizes from the $spacers map (0–5). There is no .gap-auto utility class as it’s effectively the same as .gap-0.

    Spacing utilities are declared via Sass map and then generated with our utilities API.

    1.     "margin": (
    2.       responsive: true,
    3.       property: margin,
    4.       class: m,
    5.       values: map-merge($spacers, (auto: auto))
    6.     ),
    7.     "margin-x": (
    8.       responsive: true,
    9.       property: margin-right margin-left,
    10.       class: mx,
    11.       values: map-merge($spacers, (auto: auto))
    12.     ),
    13.     "margin-y": (
    14.       responsive: true,
    15.       property: margin-top margin-bottom,
    16.       class: my,
    17.       values: map-merge($spacers, (auto: auto))
    18.     ),
    19.     "margin-top": (
    20.       responsive: true,
    21.       class: mt,
    22.       values: map-merge($spacers, (auto: auto))
    23.     ),
    24.     "margin-end": (
    25.       responsive: true,
    26.       property: margin-right,
    27.       class: me,
    28.       values: map-merge($spacers, (auto: auto))
    29.     ),
    30.     "margin-bottom": (
    31.       responsive: true,
    32.       property: margin-bottom,
    33.       class: mb,
    34.       values: map-merge($spacers, (auto: auto))
    35.     ),
    36.     "margin-start": (
    37.       responsive: true,
    38.       property: margin-left,
    39.       class: ms,
    40.       values: map-merge($spacers, (auto: auto))
    41.     ),
    42.     // Negative margin utilities
    43.     "negative-margin": (
    44.       responsive: true,
    45.       property: margin,
    46.       class: m,
    47.       values: $negative-spacers
    48.     ),
    49.     "negative-margin-x": (
    50.       responsive: true,
    51.       property: margin-right margin-left,
    52.       class: mx,
    54.     ),
    55.     "negative-margin-y": (
    56.       responsive: true,
    57.       property: margin-top margin-bottom,
    58.       class: my,
    59.       values: $negative-spacers
    60.     ),
    61.     "negative-margin-top": (
    62.       responsive: true,
    63.       property: margin-top,
    64.       class: mt,
    65.       values: $negative-spacers
    66.     ),
    67.     "negative-margin-end": (
    68.       responsive: true,
    69.       property: margin-right,
    70.       class: me,
    71.       values: $negative-spacers
    72.     ),
    73.     "negative-margin-bottom": (
    74.       property: margin-bottom,
    75.       class: mb,
    76.       values: $negative-spacers
    77.     ),
    78.     "negative-margin-start": (
    79.       responsive: true,
    80.       property: margin-left,
    81.       class: ms,
    82.       values: $negative-spacers
    83.     ),
    84.     // Padding utilities
    85.     "padding": (
    86.       responsive: true,
    87.       property: padding,
    88.       class: p,
    89.       values: $spacers
    90.     ),
    91.     "padding-x": (
    92.       responsive: true,
    93.       property: padding-right padding-left,
    94.       class: px,
    95.       values: $spacers
    96.     ),
    97.     "padding-y": (
    98.       responsive: true,
    99.       property: padding-top padding-bottom,
    100.       class: py,
    101.       values: $spacers
    102.     ),
    103.     "padding-top": (
    104.       responsive: true,
    105.       property: padding-top,
    106.       class: pt,
    107.       values: $spacers
    108.     ),
    109.     "padding-end": (
    110.       responsive: true,
    111.       property: padding-right,
    112.       class: pe,
    113.       values: $spacers
    114.     ),
    115.     "padding-bottom": (
    116.       responsive: true,
    117.       property: padding-bottom,
    118.       class: pb,
    119.       values: $spacers
    120.     ),
    121.     "padding-start": (
    122.       responsive: true,
    123.       property: padding-left,
    124.       class: ps,
    125.       values: $spacers
    126.     ),