discourse/app/assets/stylesheets/desktop/header.scss

// --------------------------------------------------
// Discourse header
// --------------------------------------------------

.d-header {
  min-width: 100%;
  position: absolute;
  top: 0;
  left: 0;
  z-index: 1000;
  box-shadow: 0 2px 4px -2px rgba($primary, .25);
  background-color: $secondary;
  padding-top: 3px;
  .docked & {
    position: fixed;
  }
  .contents {
    margin: 10px 0;
  }
  .title {
    display: table;
    float: left;
    height: 40px;
    > a {
      display: table-cell;
      vertical-align: middle;
    }
  }
  #site-logo {
    max-height: 40px;
  }
  .fa-home {
    font-size: 20px;
    line-height: 40px;
    padding-right: 3px;
    padding-top: 3px;
  }
  .panel {
    float: right;
    position: relative;
  }
  .current-username {
    float: left;
    a {
      color: $primary;
      font-size: 14px;
      display:block;
      margin-top: 10px;
    }
    button {
      margin-top: 9px;
    }
  }
  .icons {
    float: left;
    text-align: center;
    margin: 0 0 0 5px;
    list-style: none;
    > li {
      float: left;
    }
    .icon {
      display: block;
      padding: 3px;
      color: scale-color($primary, $lightness: 50%);
      text-decoration: none;
      cursor: pointer;
      border-top: 1px solid transparent;
      border-left: 1px solid transparent;
      border-right: 1px solid transparent;


      &:hover {
        color: $primary;
        background-color:  scale-color($primary, $lightness: 90%);
        border-top: 1px solid transparent;
        border-left: 1px solid transparent;
        border-right: 1px solid transparent;
      }
      &:active {
        color: $primary;
        background-color: scale-color($primary, $lightness: 90%);
      }
    }
    .active .icon {
      position: relative;
      color: #7b7b7b;
      background-color: $secondary;
      cursor: default;
      border-top: 1px solid scale-color($primary, $lightness: 90%);
      border-left: 1px solid scale-color($primary, $lightness: 90%);
      border-right: 1px solid scale-color($primary, $lightness: 90%);
      &:after {
        display: block;
        position: absolute;
        top: 100%;
        left: 0;
        z-index: 1101;
        width: 100%;
        height: 0;
        content: "";
        border-top: 1px solid $secondary;
      }
      &:hover {
      border-bottom: none;
      }
    }
    [class^="fa fa-"] {
      width: 32px;
      height: 32px;
      font-size: 20px;
      line-height: 32px;
      display: inline-block;
    }
    .notifications {
      position: relative;
    }
    .badge-notification {
      position: absolute;
      top: -9px;
      z-index: 1;
      margin-left: 0;
    }
    .unread-notifications {
      right: -4px;
      background-color: $tertiary;
    }
    .unread-private-messages {
      left: -4px;
      background-color: $success;
    }
  }
  .flagged-posts {
    background-color: $danger;
  }
}

#main {
  position: relative;
}

#main-outlet {
  padding-top: 82px;
}

// Dropdowns
// --------------------------------------------------

.d-dropdown {
  display: none;
  position: absolute;
  width: 320px;
  max-height: 417px;
  top: 100%;
  right: 0;
  z-index: 1100;
  overflow: auto;
  border: 1px solid scale-color($primary, $lightness: 90%);
  background-color: $secondary;
  @include box-shadow(0 2px 2px rgba($primary, .4));

  // Common

  ul {
    margin: 0;
    list-style: none;
  }
  li {
    padding: 5px;
    font-size: 13px;
    line-height: 16px;
    .fa {
      margin-right: 3px;
    }
  }
  .heading {
    border-top: 1px solid scale-color($primary, $lightness: 90%);

    border-bottom: 1px solid scale-color($primary, $lightness: 90%);
    color: darken($primary, 40%);
    font-weight: bold;
    font-size: 12px;
    line-height: 15px;
  }
  .selected {
    background-color: scale-color($tertiary, $lightness: 75%);
  }

  // Notifications

  &#notifications-dropdown {
    .fa {
      color: scale-color($primary, $lightness: 50%);
    }
    li {
      background-color: scale-color($tertiary, $lightness: 75%);
    }
    .read {
      background-color: $secondary;
    }
    .none {
      padding: 5px;
    }
  }

  // Search

  input[type='text'] {
    width: 298px;
    height: 22px;
    margin: 5px;
    padding: 5px;
  }
  .searching {
    display: block;
    position: absolute;
    top: 13px;
    right: 13px;
    color: scale-color($primary, $lightness: 50%);
    font-size: 18px;
  }
  .no-results {
    padding: 0 5px 5px;
  }
  .filter {
    float: right;
  }

  // Categories

  .category {
    float: left;
    background-color: transparent;
    line-height: 20px;
  }

  &#user-dropdown {
    width: 118px;
    .user-dropdown-links {
    text-align: right;

    }
  }

  .btn {
    padding: 2px 8px;
    margin-bottom: 2px;
    .fa {
      margin-right: 5px;
    }
  }
}