Utilities for layout
For faster mobile-friendly and responsive development, Bootstrap includes dozens of utility classes for showing, hiding, aligning, and spacing content.
Changing display
Use our display utilities for responsively toggling common values of the display
property. Mix it with our grid system, content, or components to show or hide them across specific viewports.
Flexbox options
Bootstrap 4 is built with flexbox, but not every element’s display
has been changed to display: flex
as this would add many unnecessary overrides and unexpectedly change key browser behaviors. Most of our components are built with flexbox enabled.
Should you need to add display: flex
to an element, do so with .d-flex
or one of the responsive variants (e.g., .d-sm-flex
). You’ll need this class or display
value to allow the use of our extra flexbox utilities for sizing, alignment, spacing, and more.
Margin and padding
Use the margin
and padding
spacing utilities to control how elements and components are spaced and sized. Bootstrap 4 includes a five-level scale for spacing utilities, based on a 1rem
value default $spacer
variable. Choose values for all viewports (e.g., .mr-3
for margin-right: 1rem
), or pick responsive variants to target specific viewports (e.g., .mr-md-3
for margin-right: 1rem
starting at the md
breakpoint).
Toggle visibility
When toggling display
isn’t needed, you can toggle the visibility
of an element with our visibility utilities. Invisible elements will still affect the layout of the page, but are visually hidden from visitors.