<p class="lead">{{_i}}Bootstrap is built on a responsive 12-column grid. We've also included fixed- and fluid-width layouts based on that system.{{/i}}</p>
<p>{{_i}}It also has four responsive variations for various devices and resolutions: phone, tablet portrait, table landscape and small desktops, and large widescreen desktops.{{/i}}</p>
<p>{{_i}}As shown here, a basic layout can be created with two "columns," each spanning a number of the 12 foundational columns we defined as part of our grid system.{{/i}}</p>
<p>{{_i}}With the static (non-fluid) grid system in Bootstrap, nesting is easy. To nest your content, just add a new <code>.row</code> and set of <code>.span*</code> columns within an existing <code>.span*</code> column.{{/i}}</p>
<p>{{_i}}Nested rows should include a set of columns that add up to the number of columns of it's parent. For example, two nested <code>.span3</code> columns should be placed within a <code>.span6</code>.{{/i}}</p>
<h1>{{_i}}Fluid grid system <small>12 responsive, percent-based columns</small>{{/i}}</h1>
</div>
<h2>{{_i}}Fluid columns{{/i}}</h2>
<div class="row-fluid show-grid">
<div class="span1">1</div>
<div class="span1">1</div>
<div class="span1">1</div>
<div class="span1">1</div>
<div class="span1">1</div>
<div class="span1">1</div>
<div class="span1">1</div>
<div class="span1">1</div>
<div class="span1">1</div>
<div class="span1">1</div>
<div class="span1">1</div>
<div class="span1">1</div>
</div>
<div class="row-fluid show-grid">
<div class="span4">4</div>
<div class="span4">4</div>
<div class="span4">4</div>
</div>
<div class="row-fluid show-grid">
<div class="span4">4</div>
<div class="span8">8</div>
</div>
<div class="row-fluid show-grid">
<div class="span6">6</div>
<div class="span6">6</div>
</div>
<div class="row-fluid show-grid">
<div class="span12">12</div>
</div>
<div class="row">
<div class="span4">
<h3>{{_i}}Percents, not pixels{{/i}}</h3>
<p>{{_i}}The fluid grid system uses percents for column widths instead of fixed pixels. It also has the same responsive variations as our fixed grid system, ensuring proper proportions for key screen resolutions and devices.{{/i}}</p>
</div>
<div class="span4">
<h3>{{_i}}Fluid rows{{/i}}</h3>
<p>{{_i}}Make any row fluid simply by changing <code>.row</code> to <code>.row-fluid</code>. The columns stay the exact same, making it super straightforward to flip between fixed and fluid layouts.{{/i}}</p>
<p>{{_i}}Nesting with fluid grids is a bit different: the number of nested columns doesn't need to match the parent. Instead, your columns are reset at each level because each row takes up 100% of the parent column.{{/i}}</p>
<p>{{_i}}Built into Bootstrap are a handful of variables for customizing the default 940px grid system, documented above. All variables for the grid are stored in variables.less.{{/i}}</p>
<p>{{_i}}Modifying the grid means changing the three <code>@grid*</code> variables and recompiling Bootstrap. Change the grid variables in variables.less and use one of the <a href="less.html#compiling">four ways documented to recompile</a>. If you're adding more columns, be sure to add the CSS for those in grid.less.{{/i}}</p>
<p>{{_i}}Customization of the grid only works at the default level, the 940px grid. To maintain the responsive aspects of Bootstrap, you'll also have to customize the grids in responsive.less.{{/i}}</p>
<p>{{_i}}The default and simple 940px-wide, centered layout for just about any website or page provided by a single <code><div class="container"></code>.{{/i}}</p>
<p>{{_i}}<code><div class="container-fluid"></code> gives flexible page structure, min- and max-widths, and a left-hand sidebar. It's great for apps and docs.{{/i}}</p>
<p>{{_i}}Bootstrap supports a handful of media queries in a single file to help make your projects more appropriate on different devices and screen resolutions. Here's what's included:{{/i}}</p>
<p>{{_i}}Media queries allow for custom CSS based on a number of conditions—ratios, widths, display type, etc—but usually focuses around <code>min-width</code> and <code>max-width</code>.{{/i}}</p>
<p>{{_i}}Bootstrap doesn't automatically include these media queries, but understanding and adding them is very easy and requires minimal setup. You have a few options for including the responsive features of Bootstrap:{{/i}}</p>
<p>{{_i}}<strong>Why not just include it?</strong> Truth be told, not everything needs to be responsive. Instead of encouraging developers to remove this feature, we figure it best to enable it.{{/i}}</p>
