Overview

Get the lowdown on the key pieces of Bootstrap's infrastructure, including our approach to better, faster, stronger web development.

HTML5 doctype

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.

<!DOCTYPE html>
<html lang="en">
  ...
</html>

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>.

<meta name="viewport" content="width=device-width, initial-scale=1">

You can disable zooming capabilities on mobile devices by adding user-scalable=no to the viewport meta tag. This disables zooming, meaning users are only able to scroll, and results in your site feeling a bit more like a native application. Overall, we don't recommend this on every site, so use caution!

<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no">

Bootstrap sets basic global display, typography, and link styles. Specifically, we:

  • Set background-color: #fff; 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.

Normalize.css

For improved cross-browser rendering, we use Normalize.css, a project by Nicolas Gallagher and Jonathan Neal.

Containers

Bootstrap requires a containing element to wrap site contents and house our grid system. You may choose one of two containers to use in your projects. Note that, due to padding and more, neither container is nestable.

Use .container for a responsive fixed width container.

<div class="container">
  ...
</div>

Use .container-fluid for a full width container, spanning the entire width of your viewport.

<div class="container-fluid">
  ...
</div>

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.

Introduction

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 (fixed-width) or .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 .row and .col-xs-4 are 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 .rows.
  • 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 .col-xs-4.
  • 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.

Media queries

We use the following media queries in our Less files to create the key breakpoints in our grid system.

/* Extra small devices (phones, less than 768px) */
/* No media query since this is the default in Bootstrap */

/* Small devices (tablets, 768px and up) */
@media (min-width: @screen-sm-min) { ... }

/* Medium devices (desktops, 992px and up) */
@media (min-width: @screen-md-min) { ... }

/* Large devices (large desktops, 1200px and up) */
@media (min-width: @screen-lg-min) { ... }

We occasionally expand on these media queries to include a max-width to limit CSS to a narrower set of devices.

@media (max-width: @screen-xs-max) { ... }
@media (min-width: @screen-sm-min) and (max-width: @screen-sm-max) { ... }
@media (min-width: @screen-md-min) and (max-width: @screen-md-max) { ... }
@media (min-width: @screen-lg-min) { ... }

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
Container width None (auto) 750px 970px 1170px
Class prefix .col-xs- .col-sm- .col-md- .col-lg-
# of columns 12
Column width Auto ~62px ~81px ~97px
Gutter width 30px (15px on each side of a column)
Nestable Yes
Offsets Yes
Column ordering Yes

Example: Stacked-to-horizontal

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 .row.

.col-md-1
.col-md-1
.col-md-1
.col-md-1
.col-md-1
.col-md-1
.col-md-1
.col-md-1
.col-md-1
.col-md-1
.col-md-1
.col-md-1
.col-md-8
.col-md-4
.col-md-4
.col-md-4
.col-md-4
.col-md-6
.col-md-6
<div class="row">
  <div class="col-md-1">.col-md-1</div>
  <div class="col-md-1">.col-md-1</div>
  <div class="col-md-1">.col-md-1</div>
  <div class="col-md-1">.col-md-1</div>
  <div class="col-md-1">.col-md-1</div>
  <div class="col-md-1">.col-md-1</div>
  <div class="col-md-1">.col-md-1</div>
  <div class="col-md-1">.col-md-1</div>
  <div class="col-md-1">.col-md-1</div>
  <div class="col-md-1">.col-md-1</div>
  <div class="col-md-1">.col-md-1</div>
  <div class="col-md-1">.col-md-1</div>
</div>
<div class="row">
  <div class="col-md-8">.col-md-8</div>
  <div class="col-md-4">.col-md-4</div>
</div>
<div class="row">
  <div class="col-md-4">.col-md-4</div>
  <div class="col-md-4">.col-md-4</div>
  <div class="col-md-4">.col-md-4</div>
</div>
<div class="row">
  <div class="col-md-6">.col-md-6</div>
  <div class="col-md-6">.col-md-6</div>
</div>

Example: Fluid container

Turn any fixed-width grid layout into a full-width layout by changing your outermost .container to .container-fluid.

<div class="container-fluid">
  <div class="row">
    ...
  </div>
</div>

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-xs-* .col-md-* to your columns. See the example below for a better idea of how it all works.

.col-xs-12 .col-md-8
.col-xs-6 .col-md-4
.col-xs-6 .col-md-4
.col-xs-6 .col-md-4
.col-xs-6 .col-md-4
.col-xs-6
.col-xs-6
<!-- Stack the columns on mobile by making one full-width and the other half-width -->
<div class="row">
  <div class="col-xs-12 col-md-8">.col-xs-12 .col-md-8</div>
  <div class="col-xs-6 col-md-4">.col-xs-6 .col-md-4</div>
</div>

<!-- Columns start at 50% wide on mobile and bump up to 33.3% wide on desktop -->
<div class="row">
  <div class="col-xs-6 col-md-4">.col-xs-6 .col-md-4</div>
  <div class="col-xs-6 col-md-4">.col-xs-6 .col-md-4</div>
  <div class="col-xs-6 col-md-4">.col-xs-6 .col-md-4</div>
</div>

<!-- Columns are always 50% wide, on mobile and desktop -->
<div class="row">
  <div class="col-xs-6">.col-xs-6</div>
  <div class="col-xs-6">.col-xs-6</div>
</div>

Example: Mobile, tablet, desktop

Build on the previous example by creating even more dynamic and powerful layouts with tablet .col-sm-* classes.

.col-xs-12 .col-sm-6 .col-md-8
.col-xs-6 .col-md-4
.col-xs-6 .col-sm-4
.col-xs-6 .col-sm-4
.col-xs-6 .col-sm-4
<div class="row">
  <div class="col-xs-12 col-sm-6 col-md-8">.col-xs-12 .col-sm-6 .col-md-8</div>
  <div class="col-xs-6 col-md-4">.col-xs-6 .col-md-4</div>
</div>
<div class="row">
  <div class="col-xs-6 col-sm-4">.col-xs-6 .col-sm-4</div>
  <div class="col-xs-6 col-sm-4">.col-xs-6 .col-sm-4</div>
  <!-- Optional: clear the XS cols if their content doesn't match in height -->
  <div class="clearfix visible-xs-block"></div>
  <div class="col-xs-6 col-sm-4">.col-xs-6 .col-sm-4</div>
</div>

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.

.col-xs-9
.col-xs-4
Since 9 + 4 = 13 > 12, this 4-column-wide div gets wrapped onto a new line as one contiguous unit.
.col-xs-6
Subsequent columns continue along the new line.
<div class="row">
  <div class="col-xs-9">.col-xs-9</div>
  <div class="col-xs-4">.col-xs-4<br>Since 9 + 4 = 13 &gt; 12, this 4-column-wide div gets wrapped onto a new line as one contiguous unit.</div>
  <div class="col-xs-6">.col-xs-6<br>Subsequent columns continue along the new line.</div>
</div>

Responsive column resets

With the four tiers of grids available you're bound to run into issues where, at certain breakpoints, your columns don't clear quite right as one is taller than the other. To fix that, use a combination of a .clearfix and our responsive utility classes.

.col-xs-6 .col-sm-3
Resize your viewport or check it out on your phone for an example.
.col-xs-6 .col-sm-3
.col-xs-6 .col-sm-3
.col-xs-6 .col-sm-3
<div class="row">
  <div class="col-xs-6 col-sm-3">.col-xs-6 .col-sm-3</div>
  <div class="col-xs-6 col-sm-3">.col-xs-6 .col-sm-3</div>

  <!-- Add the extra clearfix for only the required viewport -->
  <div class="clearfix visible-xs-block"></div>

  <div class="col-xs-6 col-sm-3">.col-xs-6 .col-sm-3</div>
  <div class="col-xs-6 col-sm-3">.col-xs-6 .col-sm-3</div>
</div>

In addition to column clearing at responsive breakpoints, you may need to reset offsets, pushes, or pulls. See this in action in the grid example.

<div class="row">
  <div class="col-sm-5 col-md-6">.col-sm-5 .col-md-6</div>
  <div class="col-sm-5 col-sm-offset-2 col-md-6 col-md-offset-0">.col-sm-5 .col-sm-offset-2 .col-md-6 .col-md-offset-0</div>
</div>

<div class="row">
  <div class="col-sm-6 col-md-5 col-lg-6">.col-sm-6 .col-md-5 .col-lg-6</div>
  <div class="col-sm-6 col-md-5 col-md-offset-2 col-lg-6 col-lg-offset-0">.col-sm-6 .col-md-5 .col-md-offset-2 .col-lg-6 .col-lg-offset-0</div>
</div>

Offsetting columns

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-offset-4 moves .col-md-4 over four columns.

.col-md-4
.col-md-4 .col-md-offset-4
.col-md-3 .col-md-offset-3
.col-md-3 .col-md-offset-3
.col-md-6 .col-md-offset-3
<div class="row">
  <div class="col-md-4">.col-md-4</div>
  <div class="col-md-4 col-md-offset-4">.col-md-4 .col-md-offset-4</div>
</div>
<div class="row">
  <div class="col-md-3 col-md-offset-3">.col-md-3 .col-md-offset-3</div>
  <div class="col-md-3 col-md-offset-3">.col-md-3 .col-md-offset-3</div>
</div>
<div class="row">
  <div class="col-md-6 col-md-offset-3">.col-md-6 .col-md-offset-3</div>
</div>

Nesting 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
<div class="row">
  <div class="col-sm-9">
    Level 1: .col-sm-9
    <div class="row">
      <div class="col-xs-8 col-sm-6">
        Level 2: .col-xs-8 .col-sm-6
      </div>
      <div class="col-xs-4 col-sm-6">
        Level 2: .col-xs-4 .col-sm-6
      </div>
    </div>
  </div>
</div>

Column ordering

Easily change the order of our built-in grid columns with .col-md-push-* and .col-md-pull-* modifier classes.

.col-md-9 .col-md-push-3
.col-md-3 .col-md-pull-9
<div class="row">
  <div class="col-md-9 col-md-push-3">.col-md-9 .col-md-push-3</div>
  <div class="col-md-3 col-md-pull-9">.col-md-3 .col-md-pull-9</div>
</div>

Typography

Headings

All HTML headings, <h1> through <h6>, are available. .h1 through .h6 classes are also available, for when you want to match the font styling of a heading but still want your text to be displayed inline.

h1. Bootstrap heading

Semibold 36px

h2. Bootstrap heading

Semibold 30px

h3. Bootstrap heading

Semibold 24px

h4. Bootstrap heading

Semibold 18px
h5. Bootstrap heading
Semibold 14px
h6. Bootstrap heading
Semibold 12px
<h1>h1. Bootstrap heading</h1>
<h2>h2. Bootstrap heading</h2>
<h3>h3. Bootstrap heading</h3>
<h4>h4. Bootstrap heading</h4>
<h5>h5. Bootstrap heading</h5>
<h6>h6. Bootstrap heading</h6>

Create lighter, secondary text in any heading with a generic <small> tag or the .small class.

h1. Bootstrap heading Secondary text

h2. Bootstrap heading Secondary text

h3. Bootstrap heading Secondary text

h4. Bootstrap heading Secondary text

h5. Bootstrap heading Secondary text
h6. Bootstrap heading Secondary text
<h1>h1. Bootstrap heading <small>Secondary text</small></h1>
<h2>h2. Bootstrap heading <small>Secondary text</small></h2>
<h3>h3. Bootstrap heading <small>Secondary text</small></h3>
<h4>h4. Bootstrap heading <small>Secondary text</small></h4>
<h5>h5. Bootstrap heading <small>Secondary text</small></h5>
<h6>h6. Bootstrap heading <small>Secondary text</small></h6>

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.

<p>...</p>

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.

<p class="lead">...</p>

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.

Inline text elements

Marked text

For highlighting a run of text due to its relevance in another context, use the <mark> tag.

You can use the mark tag to highlight text.

You can use the mark tag to <mark>highlight</mark> text.

Deleted text

For indicating blocks of text that have been deleted use the <del> tag.

This line of text is meant to be treated as deleted text.

<del>This line of text is meant to be treated as deleted text.</del>

Strikethrough text

For indicating blocks of text that are no longer relevant use the <s> tag.

This line of text is meant to be treated as no longer accurate.

<s>This line of text is meant to be treated as no longer accurate.</s>

Inserted text

For indicating additions to the document use the <ins> tag.

This line of text is meant to be treated as an addition to the document.

<ins>This line of text is meant to be treated as an addition to the document.</ins>

Underlined text

To underline text use the <u> tag.

This line of text will render as underlined

<u>This line of text will render as underlined</u>

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.

You may alternatively use an inline element with .small in place of any <small>.

This line of text is meant to be treated as fine print.

<small>This line of text is meant to be treated as fine print.</small>

Bold

For emphasizing a snippet of text with a heavier font-weight.

The following snippet of text is rendered as bold text.

<strong>rendered as bold text</strong>

Italics

For emphasizing a snippet of text with italics.

The following snippet of text is rendered as italicized text.

<em>rendered as italicized text</em>

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.

Justified text.

No wrap text.

<p class="text-left">Left aligned text.</p>
<p class="text-center">Center aligned text.</p>
<p class="text-right">Right aligned text.</p>
<p class="text-justify">Justified text.</p>
<p class="text-nowrap">No wrap text.</p>

Transformation classes

Transform text in components with text capitalization classes.

Lowercased text.

Uppercased text.

Capitalized text.

<p class="text-lowercase">Lowercased text.</p>
<p class="text-uppercase">Uppercased text.</p>
<p class="text-capitalize">Capitalized text.</p>

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 and to users of assistive technologies.

Basic abbreviation

An abbreviation of the word attribute is attr.

<abbr title="attribute">attr</abbr>

Initialism

Add .initialism to an abbreviation for a slightly smaller font-size.

HTML is the best thing since sliced bread.

<abbr title="HyperText Markup Language" class="initialism">HTML</abbr>

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
<address>
  <strong>Twitter, Inc.</strong><br>
  795 Folsom Ave, Suite 600<br>
  San Francisco, CA 94107<br>
  <abbr title="Phone">P:</abbr> (123) 456-7890
</address>

<address>
  <strong>Full Name</strong><br>
  <a href="mailto:#">first.last@example.com</a>
</address>

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.

<blockquote>
  <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer posuere erat a ante.</p>
</blockquote>

Blockquote options

Style and content changes for simple variations on a standard <blockquote>.

Naming a source

Add a <footer> 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
<blockquote>
  <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer posuere erat a ante.</p>
  <footer>Someone famous in <cite title="Source Title">Source Title</cite></footer>
</blockquote>

Alternate displays

Add .blockquote-reverse for a blockquote with right-aligned content.

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer posuere erat a ante.

Someone famous in Source Title
<blockquote class="blockquote-reverse">
  ...
</blockquote>

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
<ul>
  <li>...</li>
</ul>

Ordered

A list of items in which the order does explicitly matter.

  1. Lorem ipsum dolor sit amet
  2. Consectetur adipiscing elit
  3. Integer molestie lorem at massa
  4. Facilisis in pretium nisl aliquet
  5. Nulla volutpat aliquam velit
  6. Faucibus porta lacus fringilla vel
  7. Aenean sit amet erat nunc
  8. Eget porttitor lorem
<ol>
  <li>...</li>
</ol>

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
<ul class="list-unstyled">
  <li>...</li>
</ul>

Inline

Place all list items on a single line with display: inline-block; and some light padding.

  • Lorem ipsum
  • Phasellus iaculis
  • Nulla volutpat
<ul class="list-inline">
  <li>...</li>
</ul>

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.
<dl>
  <dt>...</dt>
  <dd>...</dd>
</dl>

Horizontal description

Make terms and descriptions in <dl> line up side-by-side. Starts off stacked like default <dl>s, but when the navbar expands, so do these.

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.
<dl class="dl-horizontal">
  <dt>...</dt>
  <dd>...</dd>
</dl>

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.
For example, <code>&lt;section&gt;</code> should be wrapped as inline.

User input

Use the <kbd> to indicate input that is typically entered via keyboard.

To switch directories, type cd followed by the name of the directory.
To edit settings, press ctrl + ,
To switch directories, type <kbd>cd</kbd> followed by the name of the directory.<br>
To edit settings, press <kbd><kbd>ctrl</kbd> + <kbd>,</kbd></kbd>

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>
<pre>&lt;p&gt;Sample text here...&lt;/p&gt;</pre>

You may optionally add the .pre-scrollable class, which will set a max-height of 350px and provide a y-axis scrollbar.

Variables

For indicating variables use the <var> tag.

y = mx + b

<var>y</var> = <var>m</var><var>x</var> + <var>b</var>

Sample output

For indicating blocks sample output from a program use the <samp> tag.

This text is meant to be treated as sample output from a computer program.

<samp>This text is meant to be treated as sample output from a computer program.</samp>

Tables

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.

Optional table caption.
# First Name Last Name Username
1 Mark Otto @mdo
2 Jacob Thornton @fat
3 Larry the Bird @twitter
<table>
  ...
</table>

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.

<form>
  <div class="form-group">
    <label for="exampleInputEmail1">Email address</label>
    <input type="email" class="form-control" id="exampleInputEmail1" placeholder="Enter email">
  </div>
  <div class="form-group">
    <label for="exampleInputPassword1">Password</label>
    <input type="password" class="form-control" id="exampleInputPassword1" placeholder="Password">
  </div>
  <button type="submit" class="btn btn-lg btn-default">Submit</button>
</form>

Inline form

Add .form-inline to your form (which doesn't have to be a <form>) for left-aligned and inline-block controls. This only applies to forms within viewports that are at least 768px wide.

May require custom widths

Inputs and selects have width: 100%; applied by default in Bootstrap. Within inline forms, we reset that to width: auto; so multiple controls can reside on the same line. Depending on your layout, additional custom widths may be required.

Always add labels

Screen readers will have trouble with your forms if you don't include a label for every input. For these inline forms, you can hide the labels using the .sr-only class. There are further alternative methods of providing a label for assistive technologies, such as the aria-label, aria-labelledby or title attribute. If none of these is present, screen readers may resort to using the placeholder attribute, if present, but note that use of placeholder as a replacement for other labelling methods is not advised.

<form class="form-inline">
  <div class="form-group">
    <label for="exampleInputName2">Name</label>
    <input type="text" class="form-control" id="exampleInputName2" placeholder="Jane Doe">
  </div>
  <div class="form-group">
    <label for="exampleInputEmail2">Email</label>
    <input type="email" class="form-control" id="exampleInputEmail2" placeholder="jane.doe@example.com">
  </div>
  <button type="submit" class="btn btn-default">Send invitation</button>
</form>
<form class="form-inline">
  <div class="form-group">
    <label class="sr-only" for="exampleInputEmail3">Email address</label>
    <input type="email" class="form-control" id="exampleInputEmail3" placeholder="Enter email">
  </div>
  <div class="form-group">
    <label class="sr-only" for="exampleInputPassword3">Password</label>
    <input type="password" class="form-control" id="exampleInputPassword3" placeholder="Password">
  </div>
  <button type="submit" class="btn btn-default">Sign in</button>
</form>
$
.00
<form class="form-inline">
  <div class="form-group">
    <label class="sr-only" for="exampleInputAmount">Amount (in dollars)</label>
    <div class="input-group">
      <div class="input-group-addon">$</div>
      <input type="text" class="form-control" id="exampleInputAmount" placeholder="Amount">
      <div class="input-group-addon">.00</div>
    </div>
  </div>
  <button type="submit" class="btn btn-primary">Transfer cash</button>
</form>

Supported 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.

Textarea

Form control which supports multiple lines of text. Change rows attribute as necessary.

<div class="form-group">
  <label for="messageInput">Message</label>
  <textarea class="form-control" id="messageInput" rows="3" placeholder="Type your message..."></textarea>
</div>

Checkboxes

Checkboxes are for selecting one or several options in a list, while radios are for selecting one option from many.

<div class="checkbox">
  <input type="checkbox" class="switch-small" checked />
  <input type="checkbox" class="switch" checked />
  <input type="checkbox" class="switch-large" checked />
</div>

Selects

Note that many native select menus—namely in Safari and Chrome—have rounded corners that cannot be modified via border-radius properties.

<div class="form-group">
  <label for="numberSelect">Cities</label>
  <select id="numberSelect" class="select form-control">
    <option>Copenhagen</option>
    <option>Budapest</option>
    <option>Berlin</option>
    <option>London</option>
    <option>Paris</option>
  </select>
</div>

Disabled state

<div class="form-group disabled">
  <label for="messageInput">Message</label>
  <textarea class="form-control" id="messageInput" rows="3" placeholder="Type your message..." disabled></textarea>
</div>

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.

Conveying validation state to assistive technologies and colorblind users

Using these validation styles to denote the state of a form control only provides a visual, color-based indication, which will not be conveyed to users of assistive technologies - such as screen readers - or to colorblind users.

Ensure that an alternative indication of state is also provided. For instance, you can include a hint about state in the form control's <label> text itself (as is the case in the following code example), include a Glyphicon (with appropriate alternative text using the .sr-only class - see the Glyphicon examples), or by providing an additional help text block. Specifically for assistive technologies, invalid form controls can also be assigned an aria-invalid="true" attribute.

<div class="form-group has-success">
  <label class="control-label" for="inputSuccess1">Input with success 
  <span class="validation-text">Success description, if necessary...</span></label>
  <input type="text" class="form-control" id="inputSuccess1">
</div>
<div class="form-group has-warning">
  <label class="control-label" for="inputWarning1">Input with warning
  <span class="validation-text">Warning description, if necessary...</span></label>
  <input type="text" class="form-control" id="inputWarning1">
</div>
<div class="form-group has-error">
  <label class="control-label" for="inputError1">Input with error
  <span class="validation-text">Error description, if necessary...</span></label>
  <input type="text" class="form-control" id="inputError1">
</div>

Column sizing

Wrap inputs in grid columns, or any custom parent element, to easily enforce desired widths.

<div class="row">
  <div class="col-xs-2">
    <input type="text" class="form-control" placeholder=".col-xs-2">
  </div>
  <div class="col-xs-3">
    <input type="text" class="form-control" placeholder=".col-xs-3">
  </div>
  <div class="col-xs-4">
    <input type="text" class="form-control" placeholder=".col-xs-4">
  </div>
</div>

Buttons

Button tags

Use the button classes on an <a>, <button>, or <input> element.

Link
<a class="btn btn-default" href="#" role="button">Link</a>
<button class="btn btn-default" type="submit">Button</button>
<input class="btn btn-default" type="button" value="Input">
<input class="btn btn-default" type="submit" value="Submit">

Context-specific usage

While button classes can be used on <a> and <button> elements, only <button> elements are supported within our nav and navbar components.

Links acting as buttons

If the <a> elements are used to act as buttons – triggering in-page functionality, rather than navigating to another document or section within the current page – they should also be given an appropriate role="button".

Cross-browser rendering

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 bug in Firefox <30 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.

Options

Use any of the available button classes to quickly create a styled button.

<!-- Standard button -->
<button type="button" class="btn btn-default">Default</button>

<!-- Provides extra visual weight and identifies the primary action in a set of buttons -->
<button type="button" class="btn btn-primary">Primary</button>

<!-- Indicates a successful or positive action -->
<button type="button" class="btn btn-success">Success</button>

<!-- Contextual button for informational alert messages -->
<button type="button" class="btn btn-info">Info</button>

<!-- Indicates caution should be taken with this action -->
<button type="button" class="btn btn-warning">Warning</button>

<!-- Indicates a dangerous or potentially negative action -->
<button type="button" class="btn btn-danger">Danger</button>

<!-- Deemphasize a button by making it look like a link while maintaining button behavior -->
<button type="button" class="btn btn-link">Link</button>
<button type="button" class="btn btn-default outlined">Default</button>
<button type="button" class="btn btn-primary outlined">Primary</button>
<button type="button" class="btn btn-success outlined">Success</button>
<button type="button" class="btn btn-info outlined">Info</button>
<button type="button" class="btn btn-warning outlined">Warning</button>
<button type="button" class="btn btn-danger outlined">Danger</button>

Conveying meaning to assistive technologies

Using color to add meaning to a button only provides a visual indication, which will not be conveyed to users of assistive technologies – such as screen readers. Ensure that information denoted by the color is either obvious from the content itself (the visible text of the button), or is included through alternative means, such as additional text hidden with the .sr-only class.

Sizes

Fancy larger or smaller buttons? Add .btn-lg, .btn-sm, or .btn-xs for additional sizes.

<p>
  <button type="button" class="btn btn-primary btn-lg">Large button</button>
  <button type="button" class="btn btn-default btn-lg">Large button</button>
</p>
<p>
  <button type="button" class="btn btn-primary">Default button</button>
  <button type="button" class="btn btn-default">Default button</button>
</p>
<p>
  <button type="button" class="btn btn-primary btn-sm">Small button</button>
  <button type="button" class="btn btn-default btn-sm">Small button</button>
</p>
<p>
  <button type="button" class="btn btn-primary btn-xs">Extra small button</button>
  <button type="button" class="btn btn-default btn-xs">Extra small button</button>
</p>

Create block level buttons—those that span the full width of a parent— by adding .btn-block.

<button type="button" class="btn btn-primary btn-lg btn-block">Block level button</button>
<button type="button" class="btn btn-default btn-lg btn-block">Block level button</button>

Active state

Buttons will appear pressed (with a darker background, darker border, and inset shadow) when active. For <button> elements, this is done via :active. For <a> elements, it's done with .active. However, you may use .active on <button>s (and include the aria-pressed="true" attribute) should you need to replicate the active state programmatically.

Button element

No need to add :active as it's a pseudo-class, but if you need to force the same appearance, go ahead and add .active.

<button type="button" class="btn btn-primary btn-lg active">Primary button</button>
<button type="button" class="btn btn-default btn-lg active">Button</button>

Anchor element

Add the .active class to <a> buttons.

Primary link Link

<a href="#" class="btn btn-primary btn-lg active" role="button">Primary link</a>
<a href="#" class="btn btn-default btn-lg active" role="button">Link</a>

Disabled state

Make buttons look unclickable by fading them back with opacity.

Button element

Add the disabled attribute to <button> buttons.

<button type="button" class="btn btn-lg btn-primary" disabled="disabled">Primary button</button>
<button type="button" class="btn btn-default btn-lg" disabled="disabled">Button</button>

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.

Anchor element

Add the .disabled class to <a> buttons.

Primary link Link

<a href="#" class="btn btn-primary btn-lg disabled" role="button">Primary link</a>
<a href="#" class="btn btn-default btn-lg disabled" role="button">Link</a>

We use .disabled as a utility class here, similar to the common .active class, so no prefix is required.

Link functionality caveat

This class uses pointer-events: none to try to disable the link functionality of <a>s, but that CSS property is not yet standardized and isn't fully supported in Opera 18 and below, or in Internet Explorer 11. In addition, even in browsers that do support pointer-events: none, keyboard navigation remains unaffected, meaning that sighted keyboard users and users of assistive technologies will still be able to activate these links. So to be safe, use custom JavaScript to disable such links.

Images

Responsive images

Images in Bootstrap 3 can be made responsive-friendly via the addition of the .img-responsive class. This applies max-width: 100%;, height: auto; and display: block; to the image so that it scales nicely to the parent element.

To center images which use the .img-responsive class, use .center-block instead of .text-center. See the helper classes section for more details about .center-block usage.

SVG images and IE 8-10

In Internet Explorer 8-10, SVG images with .img-responsive are disproportionately sized. To fix this, add width: 100% \9; where necessary. Bootstrap doesn't apply this automatically as it causes complications to other image formats.

<img src="..." class="img-responsive" alt="Responsive image">

Image shapes

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.

A generic square placeholder image with rounded corners A generic square placeholder image where only the portion within the circle circumscribed about said square is visible A generic square placeholder image with a white border around it, making it resemble a photograph taken with an old instant camera
<img src="..." alt="..." class="img-rounded">
<img src="..." alt="..." class="img-circle">
<img src="..." alt="..." class="img-thumbnail">

Helper classes

Contextual colors

Convey meaning through color with a handful of emphasis utility classes. These may also be applied to links and will darken on hover just like our default link styles.

Fusce dapibus, tellus ac cursus commodo, tortor mauris nibh.

Nullam id dolor id nibh ultricies vehicula ut id elit.

Duis mollis, est non commodo luctus, nisi erat porttitor ligula.

Maecenas sed diam eget risus varius blandit sit amet non magna.

Etiam porta sem malesuada magna mollis euismod.

Donec ullamcorper nulla non metus auctor fringilla.

<p class="text-muted">...</p>
<p class="text-primary">...</p>
<p class="text-success">...</p>
<p class="text-info">...</p>
<p class="text-warning">...</p>
<p class="text-danger">...</p>

Dealing with specificity

Sometimes emphasis classes cannot be applied due to the specificity of another selector. In most cases, a sufficient workaround is to wrap your text in a <span> with the class.

Conveying meaning to assistive technologies

Using color to add meaning only provides a visual indication, which will not be conveyed to users of assistive technologies – such as screen readers. Ensure that information denoted by the color is either obvious from the content itself (the contextual colors are only used to reinforce meaning that is already present in the text/markup), or is included through alternative means, such as additional text hidden with the .sr-only class.

Contextual backgrounds

Similar to the contextual text color classes, easily set the background of an element to any contextual class. Anchor components will darken on hover, just like the text classes.

Nullam id dolor id nibh ultricies vehicula ut id elit.

Duis mollis, est non commodo luctus, nisi erat porttitor ligula.

Maecenas sed diam eget risus varius blandit sit amet non magna.

Etiam porta sem malesuada magna mollis euismod.

Donec ullamcorper nulla non metus auctor fringilla.

<p class="bg-primary">...</p>
<p class="bg-success">...</p>
<p class="bg-info">...</p>
<p class="bg-warning">...</p>
<p class="bg-danger">...</p>

Dealing with specificity

Sometimes contextual background classes cannot be applied due to the specificity of another selector. In some cases, a sufficient workaround is to wrap your element's content in a <div> with the class.

Conveying meaning to assistive technologies

As with contextual colors, ensure that any meaning conveyed through color is also conveyed in a format that is not purely presentational.

Close icon

Use the generic close icon for dismissing content like modals and alerts.

<button type="button" class="close" aria-label="Close"><span aria-hidden="true">&times;</span></button>

Carets

Use carets to indicate dropdown functionality and direction. Note that the default caret will reverse automatically in dropup menus.

<span class="caret"></span>

Quick floats

Float an element to the left or right with a class. !important is included to avoid specificity issues. Classes can also be used as mixins.

<div class="pull-left">...</div>
<div class="pull-right">...</div>
// Classes
.pull-left {
  float: left !important;
}
.pull-right {
  float: right !important;
}

// Usage as mixins
.element {
  .pull-left();
}
.another-element {
  .pull-right();
}

Not for use in navbars

To align components in navbars with utility classes, use .navbar-left or .navbar-right instead. See the navbar docs for details.

Center content blocks

Set an element to display: block and center via margin. Available as a mixin and class.

<div class="center-block">...</div>
// Class
.center-block {
  display: block;
  margin-left: auto;
  margin-right: auto;
}

// Usage as a mixin
.element {
  .center-block();
}

Clearfix

Easily clear floats by adding .clearfix to the parent element. Utilizes the micro clearfix as popularized by Nicolas Gallagher. Can also be used as a mixin.

<!-- Usage as a class -->
<div class="clearfix">...</div>
// Mixin itself
.clearfix() {
  &:before,
  &:after {
    content: " ";
    display: table;
  }
  &:after {
    clear: both;
  }
}

// Usage as a mixin
.element {
  .clearfix();
}

Showing and hiding content

Force an element to be shown or hidden (including for screen readers) with the use of .show and .hidden classes. These classes use !important to avoid specificity conflicts, just like the quick floats. They are only available for block level toggling. They can also be used as mixins.

.hide is available, but it does not always affect screen readers and is deprecated as of v3.0.1. Use .hidden or .sr-only instead.

Furthermore, .invisible can be used to toggle only the visibility of an element, meaning its display is not modified and the element can still affect the flow of the document.

<div class="show">...</div>
<div class="hidden">...</div>
// Classes
.show {
  display: block !important;
}
.hidden {
  display: none !important;
}
.invisible {
  visibility: hidden;
}

// Usage as mixins
.element {
  .show();
}
.another-element {
  .hidden();
}

Screen reader and keyboard navigation content

Hide an element to all devices except screen readers with .sr-only. Combine .sr-only with .sr-only-focusable to show the element again when it's focused (e.g. by a keyboard-only user). Necessary for following accessibility best practices. Can also be used as mixins.

<a class="sr-only sr-only-focusable" href="#content">Skip to main content</a>
// Usage as a mixin
.skip-navigation {
  .sr-only();
  .sr-only-focusable();
}

Image replacement

Utilize the .text-hide class or mixin to help replace an element's text content with a background image.

<h1 class="text-hide">Custom heading</h1>
// Usage as a mixin
.heading {
  .text-hide();
}

Responsive utilities

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.

Try to use these on a limited basis and avoid creating entirely different versions of the same site. Instead, use them to complement each device's presentation.

Available classes

Use a single or combination of the available classes for toggling content across viewport breakpoints.

Extra small devices Phones (<768px) Small devices Tablets (≥768px) Medium devices Desktops (≥992px) Large devices Desktops (≥1200px)
.visible-xs-* Visible
.visible-sm-* Visible
.visible-md-* Visible
.visible-lg-* Visible
.hidden-xs Visible Visible Visible
.hidden-sm Visible Visible Visible
.hidden-md Visible Visible Visible
.hidden-lg Visible Visible Visible

As of v3.2.0, the .visible-*-* classes for each breakpoint come in three variations, one for each CSS display property value listed below.

Group of classes CSS display
.visible-*-block display: block;
.visible-*-inline display: inline;
.visible-*-inline-block display: inline-block;

So, for extra small (xs) screens for example, the available .visible-*-* classes are: .visible-xs-block, .visible-xs-inline, and .visible-xs-inline-block.

The classes .visible-xs, .visible-sm, .visible-md, and .visible-lg also exist, but are deprecated as of v3.2.0. They are approximately equivalent to .visible-*-block, except with additional special cases for toggling <table>-related elements.

Print classes

Similar to the regular responsive classes, use these for toggling content for print.

Classes Browser Print
.visible-print-block
.visible-print-inline
.visible-print-inline-block
Visible
.hidden-print Visible

The class .visible-print also exists but is deprecated as of v3.2.0. It is approximately equivalent to .visible-print-block, except with additional special cases for <table>-related elements.

Test cases

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.

✔ Visible on x-small
✔ Visible on small
Medium ✔ Visible on medium
✔ Visible on large
✔ Visible on x-small and small
✔ Visible on medium and large
✔ Visible on x-small and medium
✔ Visible on small and large
✔ Visible on x-small and large
✔ Visible on small and medium

Hidden on...

Here, green checkmarks also indicate the element is hidden in your current viewport.

✔ Hidden on x-small
✔ Hidden on small
Medium ✔ Hidden on medium
✔ Hidden on large
✔ Hidden on x-small and small
✔ Hidden on medium and large
✔ Hidden on x-small and medium
✔ Hidden on small and large
✔ Hidden on x-small and large
✔ Hidden on small and medium