discourse/app/assets/stylesheets/common/select-kit/select-kit.scss

.mobile-view .select-kit.is-expanded {
  z-index: 1000;
}

.select-box-kit, .select-kit {
  border: 1px solid transparent;
  min-width: 220px;
  -webkit-box-sizing: border-box;
          box-sizing: border-box;
  display: inline-block;
  -webkit-box-orient: vertical;
  -webkit-box-direction: normal;
      -ms-flex-direction: column;
          flex-direction: column;
  position: relative;
  vertical-align: middle;
  -webkit-touch-callout: none;
  -webkit-user-select: none;
     -moz-user-select: none;
      -ms-user-select: none;
          user-select: none;

  &.is-hidden {
    display: none;
  }

  &.is-disabled {
    pointer-events: none;
  }

  &.is-expanded {
    z-index: 999;

    .select-kit-body {
      display: -webkit-box;
      display: -ms-flexbox;
      display: flex;
      -webkit-box-orient: vertical;
      -webkit-box-direction: normal;
          -ms-flex-direction: column;
              flex-direction: column;
      left: 0;
      position: absolute;
      top: 0;
    }

    .select-kit-collection, {
      border-radius: inherit;
    }
  }

  &.is-above {
    .select-kit-body {
      bottom: 0;
      top: auto;
    }

    .select-kit-filter {
      border-top: 0;
    }

    .select-kit-wrapper {
      bottom: 0;
      top: auto;
    }
  }

  .d-icon {
    opacity: 0.7;
  }

  .select-box-kit-header, .select-kit-header {
    border: 1px solid transparent;
    box-sizing: border-box;
    overflow: hidden;
    -webkit-transition: all .25s;
    -o-transition: all .25s;
    transition: all .25s;
    cursor: pointer;
    outline: none;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-align: center;
        -ms-flex-align: center;
            align-items: center;
    justify-content: space-between;
    -webkit-box-orient: horizontal;
    -webkit-box-direction: normal;
        -ms-flex-direction: row;
            flex-direction: row;
    -webkit-box-pack: justify;
        -ms-flex-pack: justify;
            justify-content: space-between;

    .selected-name {
      text-align: left;
      -webkit-box-flex: 10;
          -ms-flex: 10;
              flex: 10;
      -o-text-overflow: ellipsis;
         text-overflow: ellipsis;
      white-space: nowrap;
      overflow: hidden;
      color: inherit;
    }

    .btn-clear {
      padding: 0px 10px;
      border: 0;
      background: none;
    }

    .icon {
      margin-right: 5px;
    }

    .caret-icon {
      margin-left: 5px;
      pointer-events: none;
    }

    .d-button-label {
      display: -webkit-box;
      display: -ms-flexbox;
      display: flex;
      -webkit-box-align: center;
          -ms-flex-align: center;
              align-items: center;
      white-space: nowrap;
      overflow: hidden;

      .d-icon {
        margin-left: 5px;
        margin-right: 0;
      }
    }
  }

  .select-box-kit-body, .select-kit-body {
    display: none;
    background: $secondary;
    -webkit-box-sizing: border-box;
            box-sizing: border-box;
  }

  .select-box-kit-row, .select-kit-row {
    cursor: pointer;
    line-height: normal;
    outline: none;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-sizing: border-box;
            box-sizing: border-box;
    -webkit-box-align: center;
        -ms-flex-align: center;
            align-items: center;
    -webkit-box-pack: start;
        -ms-flex-pack: start;
            justify-content: flex-start;

    .name {
      margin: 0;
      overflow: hidden;
      -o-text-overflow: ellipsis;
         text-overflow: ellipsis;
      flex: 10;
    }

    .d-icon {
      margin-right: 5px;
    }

    &.is-highlighted {
      background: $tertiary-low;
    }

    &.is-selected {
      background: $highlight-medium;
    }

    &.is-selected.is-highlighted {
      background: $tertiary-low;
    }
  }

  .select-box-kit-collection, .select-kit-collection {
    background: $secondary;
    overflow-x: hidden;
    overflow-y: auto;
    border-radius: inherit;
    -webkit-overflow-scrolling: touch;
    margin: 0;

    .select-kit-collection {
      padding: 0;
      margin: 0;

      &:hover .select-kit-row.is-highlighted:hover {
        background: $tertiary-low;
      }
    }

    &::-webkit-scrollbar {
      -webkit-appearance: none;
      width: 10px;
    }

    &::-webkit-scrollbar-thumb {
      cursor: pointer;
      border-radius: 5px;
      background: dark-light-choose($primary-medium, $secondary-medium);
    }

    &::-webkit-scrollbar-track {
      background: transparent;
      border-radius: 0;
    }
  }

  .select-box-kit-filter, .select-kit-filter {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-align: center;
        -ms-flex-align: center;
            align-items: center;
    -webkit-box-pack: justify;
        -ms-flex-pack: justify;
            justify-content: space-between;

    .filter-input, .filter-input:focus, .filter-input:active {
      background: none;
      margin: 0;
      padding: 0;
      -webkit-box-flex: 1;
          -ms-flex: 1;
              flex: 1;
      outline: none;
      border: 0;
      border-radius: 0;
      -webkit-box-shadow: none;
              box-shadow: none;
      width: 100%;
    }

    &.is-hidden {
      width: 1px;
      height: 1px;
      border: 0;
      margin: -1px;
      padding: 0;
      overflow: hidden;
      position: fixed;
      outline: 0;
      left: 0px;
      top: 0px;
    }
  }

  .select-box-kit-wrapper, .select-kit-wrapper {
    position: absolute;
    top: 0;
    left: 0;
    background: none;
    display: none;
    -webkit-box-sizing: border-box;
            box-sizing: border-box;
    pointer-events: none;
    border: 1px solid transparent;
  }
}