SimpleSheets Grid Changes to Skeleton CSS: https://github.com/dhg/Skeleton

skeleton.css

/* Grid
-------------------------------------------------- */
.column {
  position: relative;
  float: left;
  min-height: 1px;
  padding-right: 15px;
  padding-left: 15px;
}

/* Since there are no rows, you'll need to change the nth-child if you decide to change the number of columns or your columns won't wrap correctly. */
.column:nth-child(3n+2) {
  clear: both;
}

.one-half,
.one-third,
.one-fourth {
  width: 100%;
}

@media (min-width: 550px) {
  .one-half,
  .one-fourth {
    width: 50%;
  }
}
@media (min-width: 750px) {
  .one-third {
    width: 33.33333333%;
  }
}
@media (min-width: 1000px) {
  .one-fourth {
    width: 25%;
  }
}