Anniversary Grid System
Anniversary Grid System
Bootstrap includes a responsive, mobile first fluid grid system that appropriately scales up to 12 columns as the device or viewport size increases. It includes predefined classes for easy layout options, as well as powerful mixins for generating more semantic layouts.
Grid systems are used for creating page layouts through a series of rows and columns that house your content. Here's how the Bootstrap grid system works:
- Rows must be placed within a
.container-fluid(full-width) for proper alignment and padding.
- Use rows to create horizontal groups of columns.
- Content should be placed within columns, and only columns may be immediate children of rows.
- Predefined grid classes like
.col-xs-4are available for quickly making grid layouts. Less mixins can also be used for more semantic layouts.
- Columns create gutters (gaps between column content) via
padding. That padding is offset in rows for the first and last column via negative margin on
- The negative margin is why the examples below are outdented. It's so that content within grid columns is lined up with non-grid content.
- Grid columns are created by specifying the number of twelve available columns you wish to span. For example, three equal columns would use three
- If more than 12 columns are placed within a single row, each group of extra columns will, as one unit, wrap onto a new line.
- Grid classes apply to devices with screen widths greater than or equal to the breakpoint sizes, and override grid classes targeted at smaller devices. Therefore, e.g. applying any
.col-md-*class to an element will not only affect its styling on medium devices but also on large devices if a
.col-lg-*class is not present.
Look to the examples for applying these principles to your code.
See how aspects of the Bootstrap grid system work across multiple devices with a handy table.
Extra small devices Phones (<768px)
Small devices Tablets (≥768px)
Medium devices Desktops (≥992px)
Large devices Desktops (≥1200px)
|Grid behavior||Horizontal at all times||Collapsed to start, horizontal above breakpoints|
|Container width||None (auto)||750px||970px||1170px|
|# of columns||12|
|Gutter width||30px (15px on each side of a column)|
Using a single set of
.col-md-* grid classes, you can create a basic grid system that starts out stacked on mobile devices and tablet devices (the extra small to small range) before becoming horizontal on desktop (medium) devices. Place grid columns in any
Example: Fluid container
Turn any fixed-width grid layout into a full-width layout by changing your outermost
Example: Mobile and desktop
Don't want your columns to simply stack in smaller devices? Use the extra small and medium device grid classes by adding
.col-md-* to your columns. See the example below for a better idea of how it all works.
Example: Mobile, tablet, desktop
Build on the previous example by creating even more dynamic and powerful layouts with tablet
Example: Column wrapping
If more than 12 columns are placed within a single row, each group of extra columns will, as one unit, wrap onto a new line.
Since 9 + 4 = 13 > 12, this 4-column-wide div gets wrapped onto a new line as one contiguous unit.
Subsequent columns continue along the new line.
Move columns to the right using
.col-md-offset-* classes. These classes increase the left margin of a column by
* columns. For example,
.col-md-4 over four columns.
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).
Level 1: .col-sm-9
Level 2: .col-xs-8 .col-sm-6
Level 2: .col-xs-4 .col-sm-6
Easily change the order of our built-in grid columns with
.col-md-pull-* modifier classes.
Less mixins and variables
In addition to <a href="#grid-example-basic">prebuilt grid classes</a> for fast layouts, Bootstrap includes Less variables and mixins for quickly generating your own simple, semantic layouts.
Variables determine the number of columns, the gutter width, and the media query point at which to begin floating columns. We use these to generate the predefined grid classes documented above, as well as for the custom mixins listed below.
Mixins are used in conjunction with the grid variables to generate semantic CSS for individual grid columns.
You can modify the variables to your own custom values, or just use the mixins with their default values. Here's an example of using the default settings to create a two-column layout with a gap between.