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).
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.