Generated by SassMeister.com.

SassMeister-input-HTML.html

<div class="columns">
  <div class="column" style="background-color:#f00">
  </div>
  <div class="column" style="background-color:#0f0">
  </div>
  <div class="column" style="background-color:#00f">
  </div>
</div>

SassMeister-input.scss

// ----
// Sass (v3.3.0.rc.1)
// Compass (v0.13.alpha.10)
// ----

@import "bourbon/bourbon";
@import "neat/neat";

.column {
  @include span-columns(4 of 12, block-collapse);
  height: 200px;
  @include pad();
}

SassMeister-output.css

* {
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}

.column {
  float: left;
  display: block;
  width: 34.11922%;
  height: 200px;
  padding: 2.35765%;
}
.column:last-child {
  width: 31.76157%;
}

SassMeister-rendered.html

<div class="columns">
  <div class="column" style="background-color:#f00">
  </div>
  <div class="column" style="background-color:#0f0">
  </div>
  <div class="column" style="background-color:#00f">
  </div>
</div>