Generated by SassMeister.com.

SassMeister-input-HTML.html

<ul>
  <li></li>
  <li></li>
  <li></li>
  <li class="last"></li>
</ul>

SassMeister-input.scss

// ----
// Sass (v3.3.10)
// Compass (v1.0.0.alpha.20)
// Breakpoint (v2.4.2)
// Susy (v2.1.2)
// ----

@import "susy";
@import "breakpoint";
@import "compass";

$pointless-column-width: 1rem;

$default-layout: (
  global-box-sizing: border-box,
  columns: 12,
  container: 62.5rem,
  gutter-position: inside-static,
  column-width: $pointless-column-width,
  gutters: 1rem/$pointless-column-width
);

$medium-up-layout: (
  global-box-sizing: border-box,
  columns: 12,
  container: rem-calc(1000),
  gutter-position: inside-static,
  column-width: $pointless-column-width,
  gutters: 5rem/$pointless-column-width
);

// Set our default grid
$susy: $default-layout;

@include susy-breakpoint(800px, $medium-up-layout)
{
  @include layout($medium-up-layout);
}


ul
{
  margin:0;
  padding:0;
  list-style: none;
  @include full;
}

li
{
  @include span( 3 );
  content: '<p>Something</p>';
  background-color: black;
  list-style: none;
  
  &.last
  {
    @include span(last 3);
  }
}

SassMeister-output.css

Invalid CSS after "...clude span( 3 )": expected "}", was "content: '<p>So..."

SassMeister-rendered.html

<ul>
  <li></li>
  <li></li>
  <li></li>
  <li class="last"></li>
</ul>