You can see more details on http://twitter.github.com/bootstrap/scaffolding.html#gridSystem

Live grid example

The default Bootstrap grid system utilizes 12 columns, making for a 940px wide container without responsive features enabled. With the responsive CSS file added, the grid adapts to be 724px and 1170px wide depending on your viewport. Below 767px viewports, the columns become fluid and stack vertically.

Basic grid HTML

For a simple two column layout, create a .row and add the appropriate number of .span* columns. As this is a 12-column grid, each .span* spans a number of those 12 columns, and should always add up to 12 for each row (or the number of columns in the parent).

<div class="row">
  <div class="span4">...</div>
  <div class="span8">...</div>
</div>

Given this example, we have .span4 and .span8, making for 12 total columns and a complete row.

SHORCODE DEMOS

The shortcode is quite simple Attach the cols number near grid. Keep in mind you must use the row shortcode.

[row]
  [grid 2]
    ...
  [/grid]
  [grid 10]
    ...
  [/grid]
[row]

You can also use the grid shortcodes like this:

[grid2 first]
    ...
[/grid2]
[grid10 last]
    ...
[/grid10]

Other examples:

Offsetting columns

Move columns to the right using .offset* classes. Each class increases the left margin of a column by a whole column. For example, .offset4 moves .span4 over four columns.

<div class="row">
  <div class="span4">...</div>
  <div class="span3 offset2">...</div>
</div>

Nesting columns

To nest your content with the default grid, add a new .row and set of .span* columns within an existing .span* column. Nested rows should include a set of columns that add up to the number of columns of its parent.

<div class="row">
  <div class="span9">
    Level 1 column
    <div class="row">
      <div class="span6">Level 2</div>
      <div class="span3">Level 2</div>
    </div>
  </div>
</div>

Live fluid grid example

The fluid grid system uses percents instead of pixels for column widths. It has the same responsive capabilities as our fixed grid system, ensuring proper proportions for key screen resolutions and devices.

Basic fluid grid HTML

Make any row "fluid" by changing .row to .row-fluid. The column classes stay the exact same, making it easy to flip between fixed and fluid grids.

<div class="row-fluid">
  <div class="span4">...</div>
  <div class="span8">...</div>
</div>

Fluid offsetting

Operates the same way as the fixed grid system offsetting: add .offset* to any column to offset by that many columns.

<div class="row-fluid">
  <div class="span4">...</div>
  <div class="span4 offset2">...</div>
</div>

Fluid nesting

Nesting with fluid grids is a bit different: the number of nested columns should not match the parent's number of columns. Instead, each level of nested columns are reset because each row takes up 100% of the parent column.

<div class="row-fluid">
  <div class="span12">
    Fluid 12
    <div class="row-fluid">
      <div class="span6">Fluid 6</div>
      <div class="span6">Fluid 6</div>
    </div>
  </div>
</div>

In this photo gallery i used Simple Image Gallery (Plugin) by JoomlaWorks.gr

First gallery

Second gallery