Example: Fluid grid

.container

.span-12

.span-1 .sm-2

.span-4 .lg-6

.span-6 .lg-8

.container .fixed

.span-2 .lg-1 .md-2 .sm-4

.span-3 .lg-2 .md-4 .sm-4

.span-3 .lg-2 .md-2 .sm-4

.span-4 .lg-3 .md-4