discourse-header-submenus/common/common.scss

@function fallback($setting, $color) {
  @if not $setting or $setting == "" {
    @return $color;
  } @else {
    @return $setting;
  }
}

$item-height: 40px;
$icon-opacity: 0.7;

.top-menu {
  background: fallback($Menu_background, $primary);
  width: 100%;

  .menu-content {
    display: flex;
    align-items: center;
    justify-content: if($Invert_position == "true", flex-end, flex-start);
  }

  .menu-items {
    display: flex;
    height: $item-height;
  }

  .menu-item {
    position: relative;
    color: fallback($Menu_item_color, $secondary);
    border: none;
    padding: 0 0.5em;
    font-size: $font-up-1;
    transition: all 0.15s;
    display: flex;
    align-items: center;
    white-space: nowrap;

    &:hover,
    &:active,
    &:focus {
      background: fallback($Menu_item-active_background, $primary-low);
      color: fallback($Menu-item-active-color, $primary);
      cursor: default;
      .d-icon-caret-right {
        transform: rotate(90deg);
      }
      .d-header-dropdown {
        display: block;
        top: $item-height;
        left: 0;
        z-index: z("header") + 1;

        .rtl & {
          left: unset;
          right: 0;
        }
      }

      @if $Invert_position == "true" {
        &:last-child {
          .d-header-dropdown {
            left: unset;
            right: 0;

            .rtl & {
              right: unset;
              left: 0;
            }
          }
        }
      }
    }

    .d-icon-caret-right {
      margin-left: 0.25em;
      transition: transform 0.15s ease-in-out;

      .rtl & {
        margin-left: 0em;
        margin-right: 0.25em;
      }
    }
  }

  .d-header-dropdown {
    position: absolute;
    display: none;
  }

  .d-dropdown-menu {
    min-width: 160px;
    background: fallback($Submenu_background, $secondary);
    box-shadow: var(--shadow-menu-panel);
    margin: 0;
    list-style: none;
  }

  .submenu-link {
    display: flex;
    align-items: center;
    color: fallback($Submenu_item_color, $primary);
    padding: 0.5em;
    font-size: $font-down-1;
    white-space: nowrap;

    &:hover {
      color: fallback($Submenu_item_hover_color, $primary);
      background-color: fallback($Submenu_item_hover_background, $tertiary-low);
    }
  }

  .divider {
    border-top: solid 1px fallback($Divider_color, $primary-low);
    margin: 0.25em auto;
  }

  .d-icon {
    opacity: $icon-opacity;
    min-width: 1em;
    &:not(.d-icon-caret-right) {
      margin-right: 0.5em;

      .rtl & {
        margin-right: 0;
        margin-left: 0.5em;
      }
    }
  }
}