---
layout: default
title: CSS
slug: css
lead: "Global CSS settings, fundamental HTML elements styled and enhanced with extensible classes, and an advanced grid system."
base_url: "../"
---
Overview
Get the lowdown on the key pieces of Bootstrap's infrastructure, including our approach to better, faster, stronger web development.
HTML5 doctype required
Bootstrap makes use of certain HTML elements and CSS properties that require the use of the HTML5 doctype. Include it at the beginning of all your projects.
{% highlight html %}
...
{% endhighlight %}
Mobile first
With Bootstrap 2, we added optional mobile friendly styles for key aspects of the framework. With Bootstrap 3, we've rewritten the project to be mobile friendly from the start. Instead of adding on optional mobile styles, they're baked right into the core. In fact, Bootstrap is mobile first. Mobile first styles can be found throughout the entire library instead of in separate files.
To ensure proper rendering and touch zooming, add the viewport meta tag to your <head>.
{% highlight html %}
{% endhighlight %}
Responsive images
Images in Bootstrap 3 can be made responsive-friendly via the addition of the .img-responsive class. This applies max-width: 100%; and height: auto; to the image so that it scales nicely to the parent element.
{% highlight html %}
{% endhighlight %}
Typography and links
Bootstrap sets basic global display, typography, and link styles. Specifically, we:
Remove margin on the body
Set background-color: white; on the body
Use the @font-family-base, @font-size-base, and @line-height-base attributes as our typographic base
Set the global link color via @link-color and apply link underlines only on :hover
These styles can be found within scaffolding.less.
Easily center a page's contents by wrapping its contents in a .container. Containers set max-width at various media query breakpoints to match our grid system.
{% highlight html %}
...
{% endhighlight %}
Glyphicons
With the launch of Bootstrap 3, icons have been moved to a separate repository. This keeps the primary project as lean as possible, makes it easier for folks to swap icon libraries, and makes Glyphicons icon fonts more readily available to more people outside Bootstrap.
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 options
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
Max container width
None (auto)
728px
940px
1170px
Class prefix
.col-
.col-sm-
.col-lg-
# of columns
12
Max column width
Auto
~60px
~78px
~98px
Gutter width
30px (15px on each side of a column)
Nestable
Yes
Offsets
N/A
Yes
Column ordering
N/A
Yes
Example: Stacked-to-horizontal
Using a single set of grid classes, you can create a basic grid system that starts out stacked on mobile and tablet devices before becoming horizontal on desktop devices.
1
1
1
1
1
1
1
1
1
1
1
1
8
4
4
4
4
6
6
{% highlight html %}
1
1
1
1
1
1
1
1
1
1
1
1
8
4
4
4
4
6
6
{% endhighlight %}
Example: Combining mobile with desktop
Don't want your columns to simply stack in smaller devices? Use the small device grid system by adding .col-* classes to the existing .col-lg-* ones. See the example below for a better idea of how it all works.
8
4
4
4
4
6
6
{% highlight html %}
8
4
4
4
4
6
6
{% endhighlight %}
Example: Mobile, tablet, and desktop
Build on the previous example by creating even more dynamic and powerful layouts with tablet .col-sm-* classes.
.col-12 .col-sm-8 .col-lg-8
.col-6 .col-sm-4 .col-lg-4
.col-6 .col-sm-4 .col-lg-4
.col-6 .col-sm-4 .col-lg-4
.col-6 .col-sm-4 .col-lg-4
.col-6 .col-sm-6 .col-lg-6
.col-6 .col-sm-6 .col-lg-6
{% highlight html %}
.col-12 .col-sm-8 .col-lg-8
.col-6 .col-sm-4 .col-lg-4
.col-6 .col-sm-4 .col-lg-4
.col-6 .col-sm-4 .col-lg-4
.col-6 .col-sm-4 .col-lg-4
.col-6 .col-sm-6 .col-lg-6
.col-6 .col-sm-6 .col-lg-6
{% endhighlight %}
Need more examples?
We dive into more grid layouts in a separate page, free of chrome and documentation to better show you the power of the grid.
Move columns to the right using .col-lg-offset-* classes. These classes increase the left margin of a column by * columns. For example, .col-lg-offset-4 moves .col-lg-4 over four columns.
4
4 offset 4
3 offset 3
3 offset 3
6 offset 3
{% highlight html %}
...
...
3 offset 3
3 offset 3
...
{% endhighlight %}
Nesting columns
To nest your content with the default grid, add a new .row and set of .col-lg-* columns within an existing .col-lg-* column. Nested rows should include a set of columns that add up to 12.
Level 1: 9 columns
Level 2: 6 columns
Level 2: 6 columns
{% highlight html %}
Level 1: 9 columns
Level 2: 6 columns
Level 2: 6 columns
{% endhighlight %}
Column ordering
Easily change the order of our built-in grid columns with .col-lg-push-* and .col-lg-pull-* modifier classes.
9
3
{% highlight html %}
9
3
{% endhighlight %}
LESS mixins and variables
In addition to prebuilt grid classes for fast layouts, Bootstrap includes LESS variables and mixins for quickly generating your own simple, semantic layouts.
Variables
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.
{% highlight css %}
// Creates a wrapper for a series of columns
.make-row() {
// Negative margin the row out to align the content of columns
margin-left: (@grid-gutter-width / -2);
margin-right: (@grid-gutter-width / -2);
// Then clear the floated columns
.clearfix();
}
// Generate the columns
.make-column(@columns) {
@media (min-width: @grid-float-breakpoint) {
float: left;
// Calculate width based on number of columns available
width: percentage(@columns / @grid-columns);
}
// Prevent columns from collapsing when empty
min-height: 1px;
// Set inner padding as gutters instead of margin
padding-left: (@grid-gutter-width / 2);
padding-right: (@grid-gutter-width / 2);
}
// Generate the column offsets
.make-column-offset(@columns) {
@media (min-width: @grid-float-breakpoint) {
margin-left: percentage((@columns / @grid-columns));
}
}
{% endhighlight %}
Example usage
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.
All HTML headings, <h1> through <h6> are available.
Bootstrap heading
Semibold 38px
Bootstrap heading
Semibold 32px
Bootstrap heading
Semibold 24px
Bootstrap heading
Semibold 18px
Bootstrap heading
Semibold 16px
Bootstrap heading
Semibold 12px
{% highlight html %}
...
...
...
...
...
...
{% endhighlight %}
Body copy
Bootstrap's global default font-size is 14px, with a line-height of 1.428. This is applied to the <body> and all paragraphs. In addition, <p> (paragraphs) receive a bottom margin of half their computed line-height (10px by default).
Nullam quis risus eget urna mollis ornare vel eu leo. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Nullam id dolor id nibh ultricies vehicula.
Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Donec ullamcorper nulla non metus auctor fringilla. Duis mollis, est non commodo luctus, nisi erat porttitor ligula, eget lacinia odio sem nec elit. Donec ullamcorper nulla non metus auctor fringilla.
Maecenas sed diam eget risus varius blandit sit amet non magna. Donec id elit non mi porta gravida at eget metus. Duis mollis, est non commodo luctus, nisi erat porttitor ligula, eget lacinia odio sem nec elit.
{% highlight html %}
...
{% endhighlight %}
Lead body copy
Make a paragraph stand out by adding .lead.
Vivamus sagittis lacus vel augue laoreet rutrum faucibus dolor auctor. Duis mollis, est non commodo luctus.
{% highlight html %}
...
{% endhighlight %}
Built with Less
The typographic scale is based on two LESS variables in variables.less: @font-size-base and @line-height-base. The first is the base font-size used throughout and the second is the base line-height. We use those variables and some simple math to create the margins, paddings, and line-heights of all our type and more. Customize them and Bootstrap adapts.
Emphasis
Make use of HTML's default emphasis tags with lightweight styles.
Small text
For de-emphasizing inline or blocks of text, use the <small> tag to set text at 85% the size of the parent. Heading elements receive their own font-size for nested <small> elements.
This line of text is meant to be treated as fine print.
{% highlight html %}
This line of text is meant to be treated as fine print.
{% endhighlight %}
Bold
For emphasizing a snippet of text with a heavier font-weight.
The following snippet of text is rendered as bold text.
{% highlight html %}
rendered as bold text
{% endhighlight %}
Italics
For emphasizing a snippet of text with italics.
The following snippet of text is rendered as italicized text.
{% highlight html %}
rendered as italicized text
{% endhighlight %}
Alternate elements
Feel free to use <b> and <i> in HTML5. <b> is meant to highlight words or phrases without conveying additional importance while <i> is mostly for voice, technical terms, etc.
Alignment classes
Easily realign text to components with text alignment classes.
Left aligned text.
Center aligned text.
Right aligned text.
{% highlight html %}
Left aligned text.
Center aligned text.
Right aligned text.
{% endhighlight %}
Emphasis classes
Convey meaning through color with a handful of emphasis utility classes.
Fusce dapibus, tellus ac cursus commodo, tortor mauris nibh.
Nullam id dolor id nibh ultricies vehicula ut id elit.
Etiam porta sem malesuada magna mollis euismod.
Donec ullamcorper nulla non metus auctor fringilla.
Duis mollis, est non commodo luctus, nisi erat porttitor ligula.
Maecenas sed diam eget risus varius blandit sit amet non magna.
{% highlight html %}
...
...
...
...
...
...
{% endhighlight %}
Abbreviations
Stylized implementation of HTML's <abbr> element for abbreviations and acronyms to show the expanded version on hover. Abbreviations with a title attribute have a light dotted bottom border and a help cursor on hover, providing additional context on hover.
Basic abbreviation
For expanded text on long hover of an abbreviation, include the title attribute with the <abbr> element.
An abbreviation of the word attribute is attr.
{% highlight html %}
attr
{% endhighlight %}
Initialism
Add .initialism to an abbreviation for a slightly smaller font-size.
HTML is the best thing since sliced bread.
{% highlight html %}
HTML
{% endhighlight %}
Addresses
Present contact information for the nearest ancestor or the entire body of work. Preserve formatting by ending all lines with <br>.
Twitter, Inc.
795 Folsom Ave, Suite 600
San Francisco, CA 94107
P: (123) 456-7890
Full Name first.last@example.com
{% highlight html %}
Twitter, Inc.
795 Folsom Ave, Suite 600
San Francisco, CA 94107
P: (123) 456-7890
Full Name first.last@example.com
{% endhighlight %}
Blockquotes
For quoting blocks of content from another source within your document.
Default blockquote
Wrap <blockquote> around any HTML as the quote. For straight quotes, we recommend a <p>.
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer posuere erat a ante.
{% highlight html %}
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer posuere erat a ante.
{% endhighlight %}
Blockquote options
Style and content changes for simple variations on a standard <blockquote>.
Naming a source
Add <small> tag for identifying the source. Wrap the name of the source work in <cite>.
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer posuere erat a ante.
Someone famous in Source Title
{% highlight html %}
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer posuere erat a ante.
Someone famous in Source Title
{% endhighlight %}
Alternate displays
Use .pull-right for a floated, right-aligned blockquote.
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer posuere erat a ante.
Someone famous in Source Title
{% highlight html %}
...
{% endhighlight %}
Lists
Unordered
A list of items in which the order does not explicitly matter.
Lorem ipsum dolor sit amet
Consectetur adipiscing elit
Integer molestie lorem at massa
Facilisis in pretium nisl aliquet
Nulla volutpat aliquam velit
Phasellus iaculis neque
Purus sodales ultricies
Vestibulum laoreet porttitor sem
Ac tristique libero volutpat at
Faucibus porta lacus fringilla vel
Aenean sit amet erat nunc
Eget porttitor lorem
{% highlight html %}
...
{% endhighlight %}
Ordered
A list of items in which the order does explicitly matter.
Lorem ipsum dolor sit amet
Consectetur adipiscing elit
Integer molestie lorem at massa
Facilisis in pretium nisl aliquet
Nulla volutpat aliquam velit
Faucibus porta lacus fringilla vel
Aenean sit amet erat nunc
Eget porttitor lorem
{% highlight html %}
...
{% endhighlight %}
Unstyled
Remove the default list-style and left margin on list items (immediate children only). This only applies to immediate children list items, meaning you will need to add the class for any nested lists as well.
Lorem ipsum dolor sit amet
Consectetur adipiscing elit
Integer molestie lorem at massa
Facilisis in pretium nisl aliquet
Nulla volutpat aliquam velit
Phasellus iaculis neque
Purus sodales ultricies
Vestibulum laoreet porttitor sem
Ac tristique libero volutpat at
Faucibus porta lacus fringilla vel
Aenean sit amet erat nunc
Eget porttitor lorem
{% highlight html %}
...
{% endhighlight %}
Inline
Place all list items on a single line with inline-block and some light padding.
Lorem ipsum
Phasellus iaculis
Nulla volutpat
{% highlight html %}
...
{% endhighlight %}
Description
A list of terms with their associated descriptions.
Description lists
A description list is perfect for defining terms.
Euismod
Vestibulum id ligula porta felis euismod semper eget lacinia odio sem nec elit.
Donec id elit non mi porta gravida at eget metus.
Malesuada porta
Etiam porta sem malesuada magna mollis euismod.
{% highlight html %}
...
...
{% endhighlight %}
Horizontal description
Make terms and descriptions in <dl> line up side-by-side.
Description lists
A description list is perfect for defining terms.
Euismod
Vestibulum id ligula porta felis euismod semper eget lacinia odio sem nec elit.
Donec id elit non mi porta gravida at eget metus.
Malesuada porta
Etiam porta sem malesuada magna mollis euismod.
Felis euismod semper eget lacinia
Fusce dapibus, tellus ac cursus commodo, tortor mauris condimentum nibh, ut fermentum massa justo sit amet risus.
{% highlight html %}
...
...
{% endhighlight %}
Auto-truncating
Horizontal description lists will truncate terms that are too long to fit in the left column with text-overflow. In narrower viewports, they will change to the default stacked layout.
Code
Inline
Wrap inline snippets of code with <code>.
For example, <section> should be wrapped as inline.
{% highlight html %}
For example, <section> should be wrapped as inline.
{% endhighlight %}
Basic block
Use <pre> for multiple lines of code. Be sure to escape any angle brackets in the code for proper rendering.
<p>Sample text here...</p>
{% highlight html %}
<p>Sample text here...</p>
{% endhighlight %}
You may optionally add the .pre-scrollable class, which will set a max-height of 350px and provide a y-axis scrollbar.
Tables
Basic example
For basic styling—light padding and only horizontal dividers—add the base class .table to any <table>. It may seem super redundant, but given the widespread use of tables for other plugins like calendars and date pickers, we've opted to isolate our custom table styles.
#
First Name
Last Name
Username
1
Mark
Otto
@mdo
2
Jacob
Thornton
@fat
3
Larry
the Bird
@twitter
{% highlight html %}
...
{% endhighlight %}
Optional classes
Add any of the following classes to the .table base class.
Striped
Use .table-striped to add zebra-striping to any table row within the <tbody>.
Cross-browser compatibility
Striped tables are styled via the :nth-child CSS selector, which is not available in Internet Explorer 8.
#
First Name
Last Name
Username
1
Mark
Otto
@mdo
2
Jacob
Thornton
@fat
3
Larry
the Bird
@twitter
{% highlight html %}
...
{% endhighlight %}
Bordered
Add .table-bordered for borders on all sides of the table and cells.
#
First Name
Last Name
Username
1
Mark
Otto
@mdo
Mark
Otto
@TwBootstrap
2
Jacob
Thornton
@fat
3
Larry the Bird
@twitter
{% highlight html %}
...
{% endhighlight %}
Hover rows
Add .table-hover to enable a hover state on table rows within a <tbody>.
#
First Name
Last Name
Username
1
Mark
Otto
@mdo
2
Jacob
Thornton
@fat
3
Larry the Bird
@twitter
{% highlight html %}
...
{% endhighlight %}
Condensed
Add .table-condensed to make tables more compact by cutting cell padding in half.
#
First Name
Last Name
Username
1
Mark
Otto
@mdo
2
Jacob
Thornton
@fat
3
Larry the Bird
@twitter
{% highlight html %}
...
{% endhighlight %}
Contextual table classes
Use contextual classes to color table rows or individual cells.
Class
Description
.success
Indicates a successful or positive action
.danger
Indicates a dangerous or potentially negative action
.warning
Indicates a warning that might need attention
.active
Applies the hover color to a particular row or cell
#
Column heading
Column heading
Column heading
1
Column content
Column content
Column content
2
Column content
Column content
Column content
3
Column content
Column content
Column content
4
Column content
Column content
Column content
5
Column content
Column content
Column content
6
Column content
Column content
Column content
7
Column content
Column content
Column content
{% highlight html %}
1
Column content
Column content
Column content
{% endhighlight %}
Forms
Basic example
Individual form controls automatically receive some global styling. All textual <input>, <textarea>, and <select> elements with .form-control are set to width: 100%; by default. Wrap labels and controls in .form-group for optimum spacing.
{% highlight html %}
{% endhighlight %}
Optional layouts
Included with Bootstrap are optional form layouts for common use cases.
Inline form
Add .form-inline for left-aligned and inline-block controls for a compact layout.
Requires custom widths
Inputs, selects, and textareas are 100% wide by default in Bootstrap. To use the inline form, you'll have to set a width on the form controls used within.
{% highlight html %}
{% endhighlight %}
Horizontal form
Use Bootstrap's predefined grid classes to align labels and groups of form controls in a horizontal layout by adding .form-horizontal to the form. Doing so changes .form-groups to behave as grid rows, so no need for .row.
{% highlight html %}
{% endhighlight %}
Supported form controls
Examples of standard form controls supported in an example form layout.
Inputs
Most common form control, text-based input fields. Includes support for all HTML5 types: text, password, datetime, datetime-local, date, month, time, week, number, email, url, search, tel, and color.
Type declaration required
Inputs will only be fully styled if their type is properly declared.
{% highlight html %}
{% endhighlight %}
Textarea
Form control which supports multiple lines of text. Change rows attribute as necessary.
{% highlight html %}
{% endhighlight %}
Checkboxes and radios
Checkboxes are for selecting one or several options in a list while radios are for selecting one option from many.
Default (stacked)
{% highlight html %}
{% endhighlight %}
Inline checkboxes
Use .checkbox-inline or .radio-inline class to a series of checkboxes or radios for controls appear on the same line.
{% highlight html %}
{% endhighlight %}
Selects
Use the default option, or add multiple to show multiple options at once.
{% highlight html %}
{% endhighlight %}
Form control states
Provide feedback to users or visitors with basic feedback states on form controls and labels.
Input focus
We remove the default outline styles on some form controls and apply a box-shadow in its place for :focus.
{% highlight html %}
{% endhighlight %}
Disabled inputs
Add the disabled attribute on an input to prevent user input and trigger a slightly different look.
{% highlight html %}
{% endhighlight %}
Disabled fieldsets
Add the disabled attribute to a <fieldset> to disable all the controls within the <fieldset> at once.
Link functionality of <a> not impacted
This class will only change the appearance of <a class="btn btn-default"> buttons, not their functionality. Use custom JavaScript to disable links here.
Cross-browser compatibility
While Bootstrap will apply these styles in all browsers, Internet Explorer 9 and below don't actually support the disabled attribute on a <fieldset>. Use custom JavaScript to disable the fieldset in these browsers.
{% highlight html %}
{% endhighlight %}
Validation states
Bootstrap includes validation styles for error, warning, and success states on form controls. To use, add .has-warning, .has-error, or .has-success to the parent element. Any .control-label, .form-control, and .help-block within that element will receive the validation styles.
{% highlight html %}
{% endhighlight %}
Control sizing
Set heights using classes like .input-lg, and set widths using grid column classes like .col-lg-*.
Height sizing
Create larger or smaller form controls that match button sizes.
{% highlight html %}
{% endhighlight %}
Column sizing
Wrap inputs in grid columns, or any custom parent element, to easily enforce desired widths.
{% highlight html %}
{% endhighlight %}
Help text
Block level help text for form controls.
{% highlight html %}
A longer block of help text that breaks onto a new line and may extend beyond one line.
{% endhighlight %}
Buttons
Button options
Use any of the available button classes to quickly create a styled button.
{% highlight html %}
{% endhighlight %}
Button sizes
Fancy larger or smaller buttons? Add .btn-lg, .btn-sm, or .btn-xs for additional sizes.
{% highlight html %}
{% endhighlight %}
Create block level buttons—those that span the full width of a parent— by adding .btn-block.
{% highlight html %}
{% endhighlight %}
Disabled state
Make buttons look unclickable by fading them back 50%.
Button element
Add the disabled attribute to <button> buttons.
{% highlight html %}
{% endhighlight %}
Cross-browser compatibility
If you add the disabled attribute to a <button>, Internet Explorer 9 and below will render text gray with a nasty text-shadow that we cannot fix.
As a best practice, we highly recommend using the <button> element whenever possible to ensure matching cross-browser rendering.
Among other things, there's a Firefox bug that prevents us from setting the line-height of <input>-based buttons, causing them to not exactly match the height of other buttons on Firefox.
Images
Add classes to an <img> element to easily style images in any project.
Cross-browser compatibility
Keep in mind that Internet Explorer 8 lacks support for rounded corners.
For faster mobile-friendly development, use these utility classes for showing and hiding content by device via media query. Also included are utility classes for toggling content when printed.
Responsive classes
Class
Small devices Up to 768px
Medium devices 768px to 979px
Large devices 980px and up
.visible-sm
Visible
Hidden
Hidden
.visible-md
Hidden
Visible
Hidden
.visible-lg
Hidden
Hidden
Visible
.hidden-sm
Hidden
Visible
Visible
.hidden-md
Visible
Hidden
Visible
.hidden-lg
Visible
Visible
Hidden
Print classes
Class
Browser
Print
.visible-print
Hidden
Visible
.hidden-print
Visible
Hidden
When to use
Use on a limited basis and avoid creating entirely different versions of the same site. Instead, use them to complement each device's presentation. Responsive utilities are currently only available for block-level toggling, meaning display: none; or display: block;. Use with inline and table elements is currently not supported.
Test case
Resize your browser or load on different devices to test the responsive utility classes.
Visible on...
Green checkmarks indicate the element is visible in your current viewport.
Small✔ Visible on small
Medium✔ Visible on medium
Large✔ Visible on large
Hidden on...
Here, green checkmarks indicate the element is hidden in your current viewport.