responsive grid

_grid.scss

@include add-grid(3);
@include add-grid(6 at 500px);
@include add-grid(12 at 700px);
@include add-grid(2 8 2 at 900px);
@include add-grid(1 3 5 7 9 at 1100px);

imports

// Vendor imports
@import "breakpoint";
@import "modular-scale";
@import "color-schemer";
@import "singularitygs";
//@import "animate.sass";
@import "compass/css3";

result.css

/* line 31, ../scss/style.scss */
.content {
  width: 28.57143%;
  float: left;
  margin-right: -100%;
  margin-left: 0;
  clear: none;
}