Generated by SassMeister.com.

Extending CSS with Susy and Breakpoint.html

<main>
  <section class="containerComponent">
    <div class="leaf containerComponent-leaf">
      <label>Hello</label>
      <input value="world" />
    </div>
    <div class="leaf containerComponent-leaf">
      <label>Hello</label>
      <input value="world" />
    </div>
    <div class="leaf containerComponent-leaf">
      <label>Hello</label>
      <input value="world" />
    </div>
    <div class="leaf containerComponent-leaf">
      <label>Hello</label>
      <input value="world" />
    </div>
  </section>
 </main>
 <aside>
   <p>Without the breakpoint, the input elements are arranged in a single column.</p>
   <p>Inside the breakpoint, after the screen is large enough, the input elements form a single row.</p>
 </aside>

SassMeister-input.scss

// ----
// Sass (v3.4.7)
// Compass (v1.0.1)
// Breakpoint (v2.5.0)
// Susy (v2.1.3)
// ----

/* === Begin configuration === */
@import "susy";
@import "breakpoint";

@mixin clearfix {
  &:after {
    content: "";
    display: table;
    clear: both;
  }
}

@include border-box-sizing;

html { background: white; }

/* === End configuration === */

/* ui-responsive/sass/_layout.scss */
$grid-layout-large: (
  container: auto,
  columns: 24,
  math: static,
  column-width: 30px,
  gutters: 10px/30px,
  debug: (image: show, output: overlay)
);

$grid-layout-small: (
  container: 390px,
  columns: 12,
  math: fluid,
  column-width: auto,
  gutters: 1/3,
  debug: (image: show, output: overlay)
);

$susy: $grid-layout-small;

/* ui-responsive/scss/_breakpoints.scss */

$breakpoint-desktop: 960px;

/* your-app/css/_layout.scss */

main {
  @include container;
}

/* leaf/css/_layout.scss */

.leaf {
  label,
  input {
    @include full;
  }
}

/* container/css/_layout.scss */

.containerComponent {
  @include clearfix;
}

@include susy-breakpoint($breakpoint-desktop, $grid-layout-large) {
  main {
    @include container;
    // undo the max-width set by static math
    max-width: none;
  }
  
  .containerComponent {
    @include span(16);
    @include pre(4);
  }
  
  .containerComponent-leaf {
    &.leaf {
      @include span(4);
      // Undo the break applied by @include full;
      @include nobreak;
      
      &:last-child {
        @include last;
      }
    }
  }
}

SassMeister-output.css

/* === Begin configuration === */
*, *:before, *:after {
  -moz-box-sizing: border-box;
  -webkit-box-sizing: border-box;
  box-sizing: border-box;
}

html {
  background: white;
}

/* === End configuration === */
/* ui-responsive/sass/_layout.scss */
/* ui-responsive/scss/_breakpoints.scss */
/* your-app/css/_layout.scss */
main {
  max-width: 390px;
  margin-left: auto;
  margin-right: auto;
}
main:after {
  content: " ";
  display: block;
  clear: both;
}
head {
  display: block;
  position: fixed;
  right: 10px;
  top: 10px;
  z-index: 999;
  color: #333;
  background: rgba(255, 255, 255, 0.25);
}
head:before {
  content: "|||";
  display: block;
  padding: 5px 10px;
  font-family: sans-serif;
  font-size: 16px;
  font-weight: bold;
}
head:hover {
  background: rgba(255, 255, 255, 0.5);
  color: red;
}
head:hover ~ main, head:hover ~ body main {
  position: relative;
}
head:hover ~ main:before, head:hover ~ body main:before {
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  content: " ";
  z-index: 998;
  background-image: linear-gradient(to right, rgba(102, 102, 255, 0.25), rgba(179, 179, 255, 0.25) 75%, transparent 75%);
  background-size: 8.51064%;
  background-origin: content-box;
  background-clip: content-box;
  background-position: left top;
}

/* leaf/css/_layout.scss */
.leaf label,
.leaf input {
  clear: both;
  width: 100%;
  float: left;
  margin-left: 0;
  margin-right: 0;
}

/* container/css/_layout.scss */
.containerComponent:after {
  content: "";
  display: table;
  clear: both;
}

@media (min-width: 960px) {
  main {
    width: 950.0px;
    margin-left: auto;
    margin-right: auto;
    max-width: none;
  }
  main:after {
    content: " ";
    display: block;
    clear: both;
  }
  head:hover ~ main, head:hover ~ body main {
    position: relative;
  }
  head:hover ~ main:before, head:hover ~ body main:before {
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    content: " ";
    z-index: 998;
    background-image: linear-gradient(to right, rgba(102, 102, 255, 0.25), rgba(179, 179, 255, 0.25) 75%, transparent 75%);
    background-size: 40px;
    background-origin: content-box;
    background-clip: content-box;
    background-position: left top;
  }

  .containerComponent {
    width: 630px;
    float: left;
    margin-right: 10px;
    margin-left: 160px;
  }

  .containerComponent-leaf.leaf {
    width: 150px;
    float: left;
    margin-right: 10px;
    clear: none;
  }
  .containerComponent-leaf.leaf:last-child {
    float: right;
    margin-right: 0;
  }
}

SassMeister-rendered.html

<main>
  <section class="containerComponent">
    <div class="leaf containerComponent-leaf">
      <label>Hello</label>
      <input value="world" />
    </div>
    <div class="leaf containerComponent-leaf">
      <label>Hello</label>
      <input value="world" />
    </div>
    <div class="leaf containerComponent-leaf">
      <label>Hello</label>
      <input value="world" />
    </div>
    <div class="leaf containerComponent-leaf">
      <label>Hello</label>
      <input value="world" />
    </div>
  </section>
 </main>
 <aside>
   <p>Without the breakpoint, the input elements are arranged in a single column.</p>
   <p>Inside the breakpoint, after the screen is large enough, the input elements form a single row.</p>
 </aside>