static/js/com/dropdown/styles.scss

$color-grey: #ededed;
$padding-h: 5px;
$select-value-arrow-space: 15px + $padding-h;
$bg-color: #fff;
$border-color: #c5c5c5;
$border-radius: 3px;
$color-blue: #416ea4;

.dropdown {
  position: relative;
  display: inline-block;
}

.dropdown-selected-value {
  position: relative;
  min-width: 30px;
  border: 1px solid $border-color;
  border-radius: $border-radius;
  padding: 0 $select-value-arrow-space 0 $padding-h;
  background-color: $bg-color;

  user-select: none;
  cursor: pointer;

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

  &:after {
    position: absolute;
    top: 7px;
    right: 5px;

    width: 0;
    height: 0;
    border-style: solid;
    border-width: 4px 4px 0 4px;
    border-color: #000000 transparent transparent transparent;
    content: '';
  }

  &:hover:after {
    border-top-color: $color-blue;
  }

  .dropdown._opened &:after {
    transform: rotate(180deg);
  }
}

.dropdown-items {
  position: absolute;
  z-index: 1;
  top: 100%;
  left: 0;

  box-shadow: 0px 2px 5px 0px rgba(0, 0, 0, 0.3);
  min-width: 100%;
  background-color: $bg-color;

  display: none;

  .dropdown._opened & {
    display: block;
  }
}

.dropdown-item {
  overflow: hidden;
  padding: 1px $select-value-arrow-space 0 $padding-h;

  white-space: nowrap;
  text-overflow: ellipsis;
  cursor: pointer;

  &:hover {
    background-color: $color-grey;
  }

  &._selected {
    font-weight: bold;
    cursor: default;
  }
}