Generated by SassMeister.com. http://sassmeister.com/gist/68d64274d251aced021f

SassMeister-input-HTML.html

<div class="container">
  <div class="row heyo">
    <div class="column">
      <h1 class="h1">Hey</h1>
      <h2 class="h2">Hey</h2>
      <h3 class="h3">Hey</h3>
    </div>
    <div class="column"></div>
    <div class="column"></div>
  </div>
</div>
<div class="container">
  <div class="row heyo">
    <div class="column"></div>
    <div class="column"></div>
    <div class="column"></div>
  </div>
</div>

SassMeister-input.scss

// ----
// libsass (v3.2.5)
// ----

* {
  box-sizing: border-box;
}

.container {
  border: 3px solid green;
  margin: 0 auto;
  width: 500px;
}

.column {
  background-color: #eee;
  border: 1px solid red;
  min-height: 50px;

  &:last-child {
    margin-right: 0;
  }
  
  @media screen and (min-width: 900px) {
    float: left;
    margin-right: 5%;
    width: 30%;
  }
}

.row:before,
.row:after {
    content: " "; /* 1 */
    display: table; /* 2 */
}
.row:after {
    clear: both;
}

.heyo {
  margin-bottom: 20px;
}

.h1 {
  font-size: 1.2em;
  @media screen and (min-width: 900px) {
    font-size: 2em;
  }
}
.h2 {
  font-size: 1.15em;
  @media screen and (min-width: 900px) {
    font-size: 1.8em;
  }
}
.h3 {
  font-size: 1.1em;
  @media screen and (min-width: 900px) {
    font-size: 1.6em;
  }
}

SassMeister-output.css

* {
  box-sizing: border-box;
}

.container {
  border: 3px solid green;
  margin: 0 auto;
  width: 500px;
}

.column {
  background-color: #eee;
  border: 1px solid red;
  min-height: 50px;
}

.column:last-child {
  margin-right: 0;
}

@media screen and (min-width: 900px) {
  .column {
    float: left;
    margin-right: 5%;
    width: 30%;
  }
}

.row:before,
.row:after {
  content: " ";
  /* 1 */
  display: table;
  /* 2 */
}

.row:after {
  clear: both;
}

.heyo {
  margin-bottom: 20px;
}

.h1 {
  font-size: 1.2em;
}

@media screen and (min-width: 900px) {
  .h1 {
    font-size: 2em;
  }
}

.h2 {
  font-size: 1.15em;
}

@media screen and (min-width: 900px) {
  .h2 {
    font-size: 1.8em;
  }
}

.h3 {
  font-size: 1.1em;
}

@media screen and (min-width: 900px) {
  .h3 {
    font-size: 1.6em;
  }
}

SassMeister-rendered.html

<div class="container">
  <div class="row heyo">
    <div class="column">
      <h1 class="h1">Hey</h1>
      <h2 class="h2">Hey</h2>
      <h3 class="h3">Hey</h3>
    </div>
    <div class="column"></div>
    <div class="column"></div>
  </div>
</div>
<div class="container">
  <div class="row heyo">
    <div class="column"></div>
    <div class="column"></div>
    <div class="column"></div>
  </div>
</div>