


How do I Use the Spacing Utility Classes in Bootstrap?
In an article you encountered the Bootstrap 4 Spacing Utility Classes such as m-b-lg, which you attempted to implement in a React MeteorJS application without success. To clarify, let's explore the usage and updates of Bootstrap's spacing utilities.
Bootstrap 5 (beta 2021)
Since Bootstrap 5 introduced RTL support, the left and right concepts have been replaced with start and end, leading to changes in l- and r- spacing utilities:
- pl-* = ps-*
- pr-* = pe-*
- ml-* = ms-*
- mr-* = me-*
Bootstrap 4 (Update 2020)
Bootstrap 4's spacing utilities have evolved since its alpha release. The updated syntax is:
- Margins: m{sides}-{size}
- Padding: p{sides}-{size}
For example:
- mb-2 = margin bottom 2 spacing units
- m-0 = no margins
- pt-3 = padding top 3 spacing units
- p-1 = padding all sides 1 spacing unit
Bootstrap 4 provides 6 sizes (0-5) that represent a portion of the default .5rem spacer unit. Additionally, you can now specify x-axis (left/right) and y-axis (top/bottom) utilities:
- my-2 = margin top & bottom 2 spacing units
- mx-0 = no margins left & right
- px-3 = padding left & right 3 spacing units
Furthermore, these spacing utilities are responsive, with the smallest breakpoint (xs) implied if no breakpoint is specified:
- mt-md-2 = margin top 2 spacing units, on md (and up)
- py-sm-0 = no padding top & bottom, on sm (and up)
The above is the detailed content of How Have Bootstrap\'s Spacing Utility Classes Changed in Bootstrap 4 and 5?. For more information, please follow other related articles on the PHP Chinese website!

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