Containers
Containers are the most basic layout element in Bootstrap and are required when using our default grid system. Containers are used to contain, pad, and (sometimes) center the content within them. While containers can be nested, most layouts do not require a nested container.
Bootstrap comes with three different containers:
-
.container
, which sets amax-width
at each responsive breakpoint -
.container-fluid
, which iswidth: 100%
at all breakpoints -
.container-{breakpoint}
, which iswidth: 100%
until the specified breakpoint
The table below illustrates how each container’s max-width
compares to the original .container
and .container-fluid
across each breakpoint.
See them in action and compare them in our Grid example.
Extra small <576px |
Small ≥576px |
Medium ≥768px |
Large ≥992px |
Extra large ≥1200px |
|
---|---|---|---|---|---|
.container |
100% | 540px | 720px | 960px | 1140px |
.container-sm |
100% | 540px | 720px | 960px | 1140px |
.container-md |
100% | 100% | 720px | 960px | 1140px |
.container-lg |
100% | 100% | 100% | 960px | 1140px |
.container-xl |
100% | 100% | 100% | 100% | 1140px |
.container-fluid |
100% | 100% | 100% | 100% | 100% |
All-in-one
Our default .container
class is a responsive, fixed-width container, meaning its max-width
changes at each breakpoint.
Fluid
Use .container-fluid
for a full width container, spanning the entire width of the viewport.
Responsive
Responsive containers are new in Bootstrap v4.4. They allow you to specify a class that is 100% wide until the specified breakpoint is reached, after which we apply max-width
s for each of the higher breakpoints. For example, .container-sm
is 100% wide to start until the sm
breakpoint is reached, where it will scale up with md
, lg
, and xl
.
Responsive breakpoints
Since Bootstrap is developed to be mobile first, we use a handful of media queries to create sensible breakpoints for our layouts and interfaces. These breakpoints are mostly based on minimum viewport widths and allow us to scale up elements as the viewport changes.
Bootstrap primarily uses the following media query ranges—or breakpoints—in our source Sass files for our layout, grid system, and components.
Since we write our source CSS in Sass, all our media queries are available via Sass mixins:
We occasionally use media queries that go in the other direction (the given screen size or smaller):
Note that since browsers do not currently support range context queries, we work around the limitations of min-
and max-
prefixes and viewports with fractional widths (which can occur under certain conditions on high-dpi devices, for instance) by using values with higher precision for these comparisons.
Once again, these media queries are also available via Sass mixins:
There are also media queries and mixins for targeting a single segment of screen sizes using the minimum and maximum breakpoint widths.
These media queries are also available via Sass mixins:
Similarly, media queries may span multiple breakpoint widths:
The Sass mixin for targeting the same screen size range would be:
Z-index
For material approach to z-index, refer to page Elevation and shadows.