# Grid
We use the powerful mobile-first flexbox grid from Bootstrap (opens new window) to build layouts. Below you'll find the (slightly modified) documentation.
# How it works
Bootstrap's grid system uses a series of rows and columns to layout and align content. It's built with flexbox (opens new window) and is fully responsive. Below is an example and an in-depth look at how the grid comes together.
New to or unfamiliar with flexbox? Read this CSS Tricks flexbox guide (opens new window) for background, terminology, guidelines, and code snippets.
The above example creates three equal-width columns on small, medium, large, and extra large devices using our predefined grid classes.
Breaking it down, here's how it works:
- Rows are wrappers for columns. Each column has horizontal
padding(called a gutter) for controlling the space between them. Thispaddingis then counteracted on the rows with negative margins. This way, all the content in your columns is visually aligned down the left side. - In a grid layout, content must be placed within columns and only columns may be immediate children of rows.
- Thanks to flexbox, grid columns without a specified
widthwill automatically layout as equal width columns. For example, four instances of.col-smwill each automatically be 25% wide from the small breakpoint and up. See the auto-layout columns section for more examples. - Column classes indicate the number of columns you'd like to use out of the possible 12 per row. So, if you want three equal-width columns across, you can use
.col-4. - Column
widths are set in percentages, so they're always fluid and sized relative to their parent element. - Columns have horizontal
paddingto create the gutters between individual columns, however, you can remove themarginfrom rows andpaddingfrom columns with.no-gutterson the.row. - To make the grid responsive, there are five grid breakpoints - extra small, small, medium, large, and extra large.
- Grid breakpoints are based on minimum width media queries, meaning they apply to that one breakpoint and all those above it (e.g.,
.col-sm-4applies to small, medium, large, and extra large devices, but not the firstxsbreakpoint).
# Grid options
While Bootstrap uses ems or rems for defining most sizes, pxs are used for grid breakpoints and container widths. This is because the viewport width is in pixels and does not change with the font size (opens new window).
See how aspects of the Bootstrap grid system work across multiple devices with a handy table.
|
Extra small <576px |
Small ≥576px |
Medium ≥768px |
Large ≥992px |
Extra large ≥1200px | |
|---|---|---|---|---|---|
| Max container width | None (auto) | 540px | 720px | 960px | 1140px |
| Class prefix | .col- | .col-sm- | .col-md- | .col-lg- | .col-xl- |
| # of columns | 12 | ||||
| Gutter width | 1 rem (0.5 rem on each side of a column) | ||||
| Nestable | Yes | ||||
| Column ordering | Yes | ||||
# Auto-layout columns
Utilize breakpoint-specific column classes for easy column sizing without an explicit numbered class like .col-sm-6.
# Equal-width
For example, here are two grid layouts that apply to every device and viewport, from xs to xl. Add any number of unit-less classes for each breakpoint you need and every column will be the same width.
# Setting one column width
Auto-layout for flexbox grid columns also means you can set the width of one column and have the sibling columns automatically resize around it. You may use predefined grid classes (as shown below), grid mixins, or inline widths. Note that the other columns will resize no matter the width of the center column.
# Variable width content
Use col-{breakpoint}-auto classes to size columns based on the natural width of their content.
# Equal-width multi-row
Create equal-width columns that span multiple rows by inserting a .w-100 where you want the columns to break to a new line. Make the breaks responsive by mixing the .w-100 with some responsive display utilities.
# Responsive classes
Bootstrap's grid includes five tiers of predefined classes for building complex responsive layouts. Customize the size of your columns on extra small, small, medium, large, or extra large devices however you see fit.
# Stacked to horizontal
Using a single set of .col-sm-* classes, you can create a basic grid system that starts out stacked and becomes horizontal at the small breakpoint (sm).
# Mix and match
Don't want your columns to simply stack in some grid tiers? Use a combination of different classes for each tier as needed. See the example below for a better idea of how it all works.
# Alignment
Use flexbox alignment utilities to vertically and horizontally align columns.
# Vertical alignment
# Horizontal alignment
# No gutters
The gutters between columns in our predefined grid classes can be removed with .no-gutters. This removes the negative margins from .row and the horizontal padding from all immediate children columns.
In practice, here's how it looks. Note you can continue to use this with all other predefined grid classes (including column widths, responsive tiers, reorders, and more).
# Reordering
# Order classes
Use .order- classes for controlling the visual order of your content. These classes are responsive, so you can set the order by breakpoint (e.g., .order-1.order-md-2). Includes support for 1 through 12 across all five grid tiers.
There are also responsive .order-first and .order-last classes that change the order of an element by applying order: -1 and order: 13 (order: $columns + 1), respectively. These classes can also be intermixed with the numbered .order-* classes as needed.
# Offsetting columns
You can offset grid columns in two ways: our responsive .offset- grid classes and our margin utilities. Grid classes are sized to match columns while margins are more useful for quick layouts where the width of the offset is variable.
# Offset classes
Move columns to the right using .offset-md-* classes. These classes increase the left margin of a column by * columns. For example, .offset-md-4 moves .col-md-4 over four columns.
In addition to column clearing at responsive breakpoints, you may need to reset offsets.
# Margin utilities
With the move to flexbox in v4, you can use margin utilities like .mr-auto to force sibling columns away from one another.
# Nesting
To nest your content with the default grid, add a new .row and set of .col-sm-* columns within an existing .col-sm-* column. Nested rows should include a set of columns that add up to 12 or fewer (it is not required that you use all 12 available columns).