ensl.org/app/assets/stylesheets/scss/layout/_header.scss

header.navigation {
  $navigation-background: $dark-gray;
  $navigation-color: transparentize(white, 0.3);
  $navigation-color-hover: white;
  $navigation-height: 60px;
  $navigation-nav-button-background: $base-accent-color;
  $navigation-nav-button-background-hover: lighten($navigation-background, 10);
  $navigation-nav-button-border: 1px solid lighten($navigation-nav-button-background, 20);
  $navigation-search-background: lighten($navigation-background, 5);
  $navigation-search-border: 1px solid darken($navigation-background, 5);

  background-color: $navigation-background;
  border-bottom: 1px solid darken($navigation-background, 10);
  font-family: $sans-serif;
  height: $navigation-height;
  width: 100%;
  z-index: 999;

  .menu-wrapper {
    @include outer-container;
    position: relative;
    z-index: 9999;
  }

  .logo {
    float: left;    
    max-height: $navigation-height;
    padding-left: 1em;
    padding-right: 2em;

    img {
      max-height: $navigation-height;
      padding: .8em 0;
    }
  }

  .navigation-menu-button {
    color: $navigation-color;
    cursor: pointer;
    display: block;
    float: right;
    font-family: $sans-serif;
    font-weight: 700;
    line-height: $navigation-height;
    margin: 0;
    padding-right: 1em;
    text-transform: uppercase;

    @include media ($large-screen) {
      display: none;
    }

    &:hover {
      color: $navigation-color-hover;
    }
  }

  .nav {
    @include media ($large-screen) {
      float: left;
    }
  }

  ul#navigation-menu {    
    clear: both;
    -webkit-transform-style: preserve-3d; // stop webkit flicker
    display: none;
    margin: 0 auto;
    overflow: hidden;
    padding: 0;
    width: 100%;
    z-index: 9999;

    @include media ($large-screen) {
      display: inline;
      margin: 0;
      padding: 0;
    }
  }

  ul li {
    background: $navigation-background;
    display: block;
    line-height: $navigation-height;
    overflow: hidden;
    padding-right: .8em;
    text-align: right;
    width: 100%;
    z-index: 9999;

    @include media ($large-screen) {
      background: transparent;
      display: inline;
      line-height: $navigation-height;
      padding-right: 2em;
      text-decoration: none;
      width: auto;
    }

    a {
      font-weight: 400;
      color: $navigation-color;

      &:hover {
        color: $navigation-color-hover;
      }
    }
  }

  .sign-up {
    @include media ($large-screen) {
      @include position(absolute, 0px 0px 0 0);
      padding-right: 1em;

      a {
        @include transition (all 0.2s ease-in-out);
        background: $navigation-nav-button-background;
        border-radius: $base-border-radius; 
        color: white;
        font-size: .8em;  
        font-weight: 800;
        padding: .6em 1em;
        text-transform: uppercase;

        &:hover {
          background: lighten($navigation-nav-button-background, 10);
        }
      }
    }
  }

  li.navigation-search-bar {
    display: none;

    @include media($large-screen) {
      @include position(absolute, 0px 76px 0 0);
      display: inline-block;
      line-height: 0 !important;
      padding: 13px 30px; // this to get around Firefox/Opera line-height "bug"
    }
  }

  .search-bar {
    $search-bar-border-color: $base-border-color;
    $search-bar-border: 1px solid $search-bar-border-color;
    $search-bar-background: lighten($search-bar-border-color, 10);

    width: 19em;
    position: relative; 
    display: inline-block;

    input {
      @include box-sizing(border-box);
      display: block;
    }
    
    input[type=text] {
      background: $navigation-search-background;
      border: $navigation-search-border;
      padding: .6em .8em;
      font-size: .9em;
      font-style: italic;
      color: $navigation-color;
      border-radius: $base-border-radius * 2;
      margin: 0;
    }
  }
}