openproject/app/assets/stylesheets/layout/_tree_menu.sass

#main-menu ul ul.menu-children ul.pages-hierarchy,
.pages-hierarchy
  $hierarchy-span-width: 25px
  $tree-menu-item-height: 30px
  line-height: $tree-menu-item-height
  .tree-menu--title
    display: inline-block
    width: calc(100% - #{$hierarchy-span-width})
    vertical-align: bottom
    height: $tree-menu-item-height
    line-height: $tree-menu-item-height

  .tree-menu--hierarchy-span
    display: inline-block
    width: $hierarchy-span-width
    padding-left: 8px
    line-height: $tree-menu-item-height

  .tree-menu--hierarchy-indicator-icon,
  .tree-menu--leaf-indicator
    line-height: $tree-menu-item-height


  // Style the hierarchy group indicator arrow
  // default: open arrow down
  // collapsed: right arrow
  .tree-menu--hierarchy-indicator
    @include varprop(color, main-menu-font-color)
    height: $tree-menu-item-height
    line-height: $tree-menu-item-height

    &:hover
      text-decoration: none

  // Toggle the indicator accessibility texts
  // accordingly
  .tree-menu--hierarchy-indicator-collapsed
    display: none

  .-hierarchy-collapsed
    .tree-menu--hierarchy-indicator-expanded
      display: none
    .tree-menu--hierarchy-indicator-collapsed
      display: inline-block
  // END accessibility rules

  .tree-menu--hierarchy-indicator-icon
    @include icon-common
    @extend .icon-arrow-down1
    font-size: 0.6rem

  &.-with-hierarchy
    .-with-hierarchy
      padding-left: 1rem


  &.-hierarchy-collapsed > li
    > .tree-menu--item > .tree-menu--hierarchy-span > .tree-menu--hierarchy-indicator > .tree-menu--hierarchy-indicator-icon
      @include icon-common
      @extend .icon-arrow-right2
      font-size: 0.6rem
    > ul.-with-hierarchy
      display: none

  > li,
  > li:hover
    background: transparent

  .tree-menu--item
    display: inline-block
    width: 100%
    border-radius: 3px
    line-height: $tree-menu-item-height
    height: $tree-menu-item-height
    &:hover
      @include varprop(color, main-menu-hover-font-color)
      @include varprop(background, main-menu-bg-hover-background)