$_base_hover_color: transparentize($fg_color, 0.85);
$_base_active_color: transparentize($fg_color, 0.75);

@mixin undershoot($p) {
    //
    // undershoot
    //
    // $p: position
    //
    // possible $p values:
    // top, bottom, right, left
    //

    $_us_shadow_color: if($variant=='light', $silk, $jet);
    $_us_shadow_alpha: 0.8;

    $_gradient_dir: left;
    $_dash_bg_size: 10px 1px;
    $_gradient_repeat: repeat-x;
    $_bg_pos: center $p;

    background-color: transparent; // shouldn't be needed, but better to be sure;

    @if ($p == left) or ($p == right) {
        $_gradient_dir: top;
        $_dash_bg_size: 1px 10px;
        $_gradient_repeat: repeat-y;
        $_bg_pos: $p center;
    }

    padding-#{$p}: 1px;
    background-size: $_dash_bg_size;
    background-repeat: $_gradient_repeat;
    background-origin: content-box;
    background-position: $_bg_pos;
    border: none;

    @if ($p == left) {
        box-shadow: inset 2px 0 0 transparentize($_us_shadow_color, $_us_shadow_alpha),
        inset 1px 0 0 transparentize(darken($_us_shadow_color, 20%), $_us_shadow_alpha);
    }
    @else if ($p == right) {
        box-shadow: inset -2px 0 0 transparentize($_us_shadow_color, $_us_shadow_alpha),
        inset -1px 0 0 transparentize(darken($_us_shadow_color, 20%), $_us_shadow_alpha);
    }
    @else if ($p == top) {
        box-shadow: inset 0 2px 0 0 transparentize($_us_shadow_color, $_us_shadow_alpha),
        inset 0 1px 0 0 transparentize(darken($_us_shadow_color, 20%), $_us_shadow_alpha);
    }
    @else if ($p == bottom) {
        box-shadow: inset 0 -2px 0 0 transparentize($_us_shadow_color, $_us_shadow_alpha),
        inset 0 -1px 0 0 transparentize(darken($_us_shadow_color, 20%), $_us_shadow_alpha);
    }
}

// with a flatter headerbar and buttons, we dont need that heavy shadows, remove this when upstream agrees
headerbar *, button * {
    text-shadow: none;
    -gtk-icon-shadow: none;
}

// blue spinner, white spinner for colored buttons
spinner {
    &:not(:backdrop) {
        color: $spinner_color;
    }
    button.suggested-action &, button.destructive-action & {
        color: $selected_fg_color;
        &:backdrop { color: $backdrop_selected_fg_color; }
    }
}





windowcontrols {
button {
    &.maximize, &.minimize, &.close {
      border-radius: 6px;
      background-image: linear-gradient(to bottom,
                      $menubar_menuitem_hover_gradient_a,
                      $menubar_menuitem_hover_gradient_b 50%,
                      $menubar_menuitem_hover_gradient_c 50%,
                      $menubar_menuitem_hover_gradient_d );

      &:backdrop {
         background-image: none;
         border-color: $borders_color; 
      }

      border-color: $menubar_menuitem_hover_border_color;
      &, &:backdrop {
        &:hover {
          background-image: linear-gradient(to bottom,
                      $menubar_menuitem_hover_gradient_a,
                      $menubar_menuitem_hover_gradient_b)
        //  @include draw_circle(if($ambiance==true, lighten($inkstone, 7%), $_base_hover_color));
        }

        &:active {
           background-image: linear-gradient(to bottom,
                      darken($core_color_a, 14%),
                       darken($core_color_a, 15%))
         // @include draw_circle(if($ambiance==true, lighten($inkstone, 12%), $_base_active_color));
        }
      }
    }
}
}

// we prefered our gray hover for menus and popovers, orange is a very strong color
menu,
.menu,
.context-menu {
    item:selected {
        color: $fg_color;
        background-color: $popover_hover_color;
    }
}

// We don't want menuitems to look like links, we should propose this upstream
menubar,
.menubar {
    item:selected {
        color: $fg_color;
        background-color: $popover_hover_color;
    }
}

// We don't want the app notifications to look like OSD because they are interactive
.app-notification,
.app-notification.frame {
    padding: 0px 10px;
    margin: 12px;
    color: $text_color;
    border-radius: $menu_radius;
    background: none;
    background-color: $menu_color;
    border: 1px solid $borders_color;
    box-shadow: 0 2px 5px transparentize(black, 0.8);
    text-shadow: none;

    button {
        &, &:dir(ltr), &:dir(rtl) {
            &.text-button, &.image-button, & {
                @include button(normal);
                &.flat { @include button(undecorated); }
                &:hover { @include button(hover); }
                &:active { @include button(active); }
                &:backdrop {
                    @include button(backdrop);
                    &.flat { @include button(undecorated); }
                }
                &:disabled { @include button(insensitive); }
            }
        }
    }

    &:backdrop {
        background-color: $backdrop_bg_color;
        color: $backdrop_text_color;
        box-shadow: none;
        transition: $backdrop_transition;
    }

    border { border: none; }
}

notebook > header {
    &, &:backdrop { background: transparent; }
    tabs {
        &, &:hover, &:backdrop {
            &, &.right, &.left, &.top, &.bottom {
                background-color: transparent;
                tab {
                    outline-width: 1px;
                    outline-offset: -2px;
                    &, &:dir(ltr), &:dir(rtl) {
                        &, &:backdrop {
                            &, &:checked {
                                &, &:hover, &:active {
                                    background-color: transparent;
                                    border-color: transparent;
                                }
                            }
                            &:hover:not(:checked):not(:backdrop) { color: $insensitive_fg_color; }
                        }
                    }
                }
            }
        }
    }
}

// With the conservative tab styling scrolled windows need the undershoots
scrolledwindow {
    undershoot {
        &.top { @include undershoot(top); }

        &.bottom { @include undershoot(bottom); }

        &.left { @include undershoot(left); }

        &.right { @include undershoot(right); }
    }
}

// Check/radios in menus do not need a border
popover.menu {
    check,
    radio {
        &, &:checked, &:indeterminate {
            &, &:hover, &:disabled {
                border-color: transparent;
                background: transparent;
            }
        }
    }
}

// Fixes selected disabled check/radios leaking selected_bg_color, should move to upstream
treeview.view check,
treeview.view radio {
    &:selected {
        &:focus, & {
            &:disabled { color: $insensitive_fg_color; }
        }
    }
}

// Reducing the amount of the palette's background colors to two
.sidebar { background-color: $bg_color; }

scale {
    > trough > slider {
        .osd & {
            @include button(osd);
            background-image: image(darken($osd_fg_color, 2%));

            &:hover {
                background-image: image(darken($osd_fg_color, 10%));
            }

            &:active {
                background-image: image(darken($osd_fg_color, 25%));
            }
        }
    }
}

// Rubberband selection shall match with shell's tile-preview
.rubberband,
rubberband {
    background-color: transparentize($ash, 0.8);
    border: 1px solid if($variant == 'light', transparentize($silk, 0.2), transparentize(darken($silk, 10%), 0.4));
}

// Entries drown if drawn on widgets with $base_color
// Fixing this at least for notebooks, since entries on tabs is a common pattern
@if $variant=='dark' {
    notebook entry { background-color: darken($base_color, 2%); }
}

// Make all :not:(.empty) level bars green - should be moved to upstream
levelbar > trough > block {
    &.high,
    &:not(.empty) {
        border-color: $success_color;
        background-color: $success_color;
        &:backdrop { border-color: $success_color; }
    }
}

// Strengthen the menu shadows
// And lighten up the dark shell menu/popover border to increase visibility
$_dark_theme_outer_menu_border: lighten(desaturate($base_color, 100%), 14%);
decoration {
  .csd.popup & {
    box-shadow: 0 1px 2px 1px transparentize(black, if($variant=='light', 0.7, 0.6)),
                0 0 0 1px if($variant=='light', transparentize(black, 0.77), $_dark_theme_outer_menu_border);
  }
}
@if $variant=='dark' {
  menu separator {
    background-color: $_dark_theme_outer_menu_border;
  }
}
popover.background {
  .csd &, & {
    border-color: if($variant=='light', transparentize(black, 0.77), $_dark_theme_outer_menu_border);
    &:backdrop { border-color: $backdrop_borders_color; }
  }
  @if $variant=='dark' {
    separator {
      background-color: $_dark_theme_outer_menu_border;
    }
  }
}

// Add some transitions on checks and radios
check,
radio {
    transition-property: background, border;
    transition-duration: 200ms;
    transition-timing-function: ease;
}

// Due to the ubuntu orange beeing quiet bright
// we change the sidebar selection from a full orange
// row to a thin orange stripe plus a soft gray selection
$_selection_bg: if($variant=='light', darken($bg_color, 5%), lighten($base_color, 5%));
list row, placessidebar row, sidebar row, .sidebar row {
  &:selected {
    &.activatable, & {
      &, &:hover {
        background-color: $_selection_bg;
        &, button { &, & image { color: $text_color; } }
        box-shadow: inset 4px 0 0 $selected_bg_color;
        &:backdrop {
            &, button { &, & image { color: $backdrop_fg_color; } }
            background-color: if($variant=='light', $_selection_bg, lighten($_selection_bg, 2%));
        }
      }
    }
  }
}

// Adapt dark gtk3 scale and levelbar troughs to the shell
@if $variant=='dark' {
  scale, progressbar {
    > trough {
      background-color: $_dark_theme_outer_menu_border;
      &, &:disabled {
          border-color: $_dark_theme_outer_menu_border;
      }
    }
    &:backdrop {
      > trough {
        border-color: darken($_dark_theme_outer_menu_border, 5%);
        background-color: darken($_dark_theme_outer_menu_border, 5%);
      }
    }
  }
  levelbar > trough > block.empty {
    border-color: $_dark_theme_outer_menu_border;
    background-color: $_dark_theme_outer_menu_border;
    &:backdrop {
      border-color: darken($_dark_theme_outer_menu_border, 5%);
      background-color: darken($_dark_theme_outer_menu_border, 5%);
    }
  }
}

// Adapt switch and scale slider troughs to the shell
@if $variant=='dark' {
  switch, scale > trough {
    &:not(:backdrop):not(:disabled){
        > slider {
          background-image: image($warm_gray);
          background-clip: padding-box; // fix background overflow
        }

        &:hover {
          > slider {
            background-image: image(lighten($warm_gray, 4%));
          }
        }
    }
  }
}

// Reduce hyper prominent dark theme check switch border in backdrop
switch {
  @if $variant=='dark' {
    &:not(:checked):not(:backdrop):not(:disabled) { background-color: lighten($bg_color, 5%); }
  }
  &:backdrop {
    &:checked:not(:disabled) {
      &, slider { border-color: if($variant=='light', $checkradio_borders_color, $backdrop_borders_color); }
    }
  }
}

check:checked, radio:checked  {border-color:$borders_color}

tab:hover{ color: $fg_color}