There is a responsive 12 columns grid.
Add a set of .row inside your div .container, and put a set of .span[1..12] inside your rows.
Example :
.span1
.span1
.span1
.span1
.span1
.span1
.span1
.span1
.span1
.span2
.span2
.span2
.span2
.span1
.span3
.span3
.span3
Nesting columns
You can nest your content with the default grid. Simply add an new .row and a set of .span* within an existing .span* column.
Nested rows should include a set of columns that add up to the number of columns of its parent.
You can set images and videos as full-width. Nevermind the screen resolution, the object will take all the width of its parent element.
Full-width container
If you want to add a set of rows that takes all the width of the page, include them inside a div .container-full-width instead of the usual .container.
Full-width pictures
For responsive pictures, use the class .img-full-width directly on the image.
Examples :
Full-width videos
For responsive videos, use the class .video-full-width on a parent div.
Use the following helper classes to add fast effect and position to your elements : .align-left, .align-center, .align-right, .rounded, .circle, .shadow, .oval, .square and .polaroid.