Generated by SassMeister.com.

SassMeister-input-HTML.html

<p>Test</p>

SassMeister-input.scss

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

SassMeister-output.css

html {
  box-sizing: border-box;
}

*,
*::after,
*::before {
  box-sizing: inherit;
}

body {
  font-family: Arial;
}

.view__header {
  border: 1px solid #09c;
}

.header-area--ne {
  max-width: 68em;
  margin-left: auto;
  margin-right: auto;
  display: -webkit-box;
  display: -moz-box;
  display: box;
  display: -webkit-flex;
  display: -moz-flex;
  display: -ms-flexbox;
  display: flex;
  border: 1px solid gray;
}

.header-area--ne::after {
  clear: both;
  content: "";
  display: table;
}

.header-area--ne .header-area--ne__primary, .header-area--ne .header-area--ne__secondary, .header-area--ne .header-area--fb__primary, .header-area--ne .header-area--fb__secondary {
  display: -webkit-box;
  display: -moz-box;
  display: box;
  display: -webkit-flex;
  display: -moz-flex;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
  -moz-box-align: center;
  box-align: center;
  -webkit-align-items: center;
  -moz-align-items: center;
  -ms-align-items: center;
  -o-align-items: center;
  align-items: center;
  -ms-flex-align: center;
}

.header-area--ne__primary {
  background-color: lightgray;
}

.header-area--ne__secondary {
  background-color: lightblue;
}

@media screen and (max-width: 768px) {
  .header-area--ne__primary, .header-area--ne__secondary {
    max-width: 68em;
    margin-left: auto;
    margin-right: auto;
    float: left;
    display: block;
    margin-right: 2.35765%;
    width: 100%;
    justify-content: center;
    text-align: center;
  }
  .header-area--ne__primary::after, .header-area--ne__secondary::after {
    clear: both;
    content: "";
    display: table;
  }
  .header-area--ne__primary:last-child, .header-area--ne__secondary:last-child {
    margin-right: 0;
  }
}

@media screen and (min-width: 769px) {
  .header-area--ne__primary {
    float: left;
    display: block;
    margin-right: 2.35765%;
    width: 65.88078%;
    justify-content: flex-start;
    text-align: left;
  }
  .header-area--ne__primary:last-child {
    margin-right: 0;
  }
  .header-area--ne__secondary {
    float: left;
    display: block;
    margin-right: 2.35765%;
    width: 31.76157%;
    justify-content: flex-start;
    text-align: left;
  }
  .header-area--ne__secondary:last-child {
    margin-right: 0;
  }
}

.header-area--fb {
  display: flex;
  border: 1px solid gray;
  flex-direction: column;
}

.header-area--fb .header-area--ne__primary, .header-area--fb .header-area--ne__secondary, .header-area--fb .header-area--fb__primary, .header-area--fb .header-area--fb__secondary {
  display: flex;
  align-self: stretch;
  align-items: center;
  padding: 10px;
}

.header-area--fb__primary {
  flex-grow: 1;
  background-color: lightgray;
}

.header-area--fb__secondary {
  background-color: lightblue;
}

.header-area--fb__primary, .header-area--fb__secondary {
  justify-content: center;
  text-align: center;
}

@media only screen and (min-width: 768px) {
  .header-area--fb {
    flex-direction: row;
  }
  .header-area--fb__primary, .header-area--fb__secondary {
    justify-content: flex-start;
    text-align: left;
  }
}

SassMeister-rendered.html

<p>Test</p>