Colloid-gtk-theme/src/sass/libadwaita/widgets/_toolbars.scss

%toolbar {
  button:not(.raised):not(.suggested-action):not(.destructive-action):not(.opaque) {
    &.arrow-button,
    &.image-button,
    &.image-text-button {
      @extend %button_basic_flat;
    }
  }

  &.osd button:not(.raised):not(.suggested-action):not(.destructive-action):not(.opaque) {
    &:focus:focus-visible {
      outline-color: $osd_focus_color;
    }
  }

  menubutton:not(.raised):not(.suggested-action):not(.destructive-action):not(.opaque) {
    &.image-button > button {
      @extend %button_basic_flat;
    }
  }

  .linked button:not(.raised):not(.suggested-action):not(.destructive-action):not(.opaque) {
    &.arrow-button,
    &.image-button,
    &.image-text-button {
      @extend %button_basic_raised;
    }
  }

  menubutton.raised > button:not(.raised):not(.suggested-action):not(.destructive-action):not(.opaque) {
    &.arrow-button,
    &.image-button,
    &.image-text-button {
      @extend %button_basic_raised;
    }
  }

  menubutton.suggested-action,
  menubutton.destructive-action,
  menubutton.opaque {
    > button:not(.raised):not(.suggested-action):not(.destructive-action):not(.opaque) {
      @extend %opaque_button;

      color: inherit;
      background-color: transparent;
    }
  }

  splitbutton:not(.raised):not(.suggested-action):not(.destructive-action):not(.opaque) {
    @extend %flat_split_button;
  }

  switch {
    margin-top: 4px;
    margin-bottom: 4px;
  }

  // Reset styles for popovers
  popover {
    button:not(.flat):not(.raised):not(.suggested-action):not(.destructive-action):not(.opaque) {
      &.arrow-button,
      &.image-button,
      &.image-text-button {
        @extend %button_basic_raised;
      }
    }

    menubutton:not(.flat):not(.raised):not(.suggested-action):not(.destructive-action):not(.opaque) {
      &.image-button > button {
        @extend %button_basic_raised;
      }
    }
  }
}

.toolbar {
  padding: 6px;
  border-spacing: 6px;
  @extend %toolbar;

  // stand-alone OSD toolbars
  &.osd {
    padding: 12px;
    border-radius: $card_radius;
  }
}

%toolbar-shrunk {
  padding-top: 3px;
  padding-bottom: 3px;
}

/****************
 * GtkSearchBar *
 ****************/

searchbar {
  > revealer > box {
    padding: 6px 6px 7px 6px;
    background-color: $headerbar_backdrop_color;
    color: $headerbar_fg_color;
    box-shadow: inset 0 -1px $headerbar_border_color;

    &:backdrop {
      background-color: $headerbar_bg_color;
      transition: background-color $backdrop_transition;

      > * {
        filter: opacity(.5);
        transition: filter $backdrop_transition;
      }
    }

    @extend %toolbar;

   .close {
      min-width: 18px;
      min-height: 18px;
      padding: 4px;
      border-radius: 50%;
      @extend %button_basic_flat;

      &:dir(ltr) {
        margin-left: 10px;
        margin-right: 4px;
      }

      &:dir(rtl) {
        margin-left: 4px;
        margin-right: 10px;
      }
    }
  }

  &.inline {
    @extend %searchbar-inline;
  }
}

%searchbar-flat > revealer > box {
  background-color: transparent;
  color: inherit;
  box-shadow: none;
  padding-bottom: 6px;
}

%searchbar-inline {
  @extend %searchbar-flat;

  > revealer > box:backdrop {
    background-color: transparent;
    transition: none;

    > * {
      filter: none;
      transition: none;
    }
  }
}

%searchbar-shrunk > revealer > box {
  padding-top: 3px;
  padding-bottom: 3px;
}

/****************
 * GtkActionBar *
 ****************/

actionbar > revealer > box {
  background-color: $headerbar_backdrop_color;
  color: $headerbar_fg_color;
  box-shadow: inset 0 1px $headerbar_border_color;
  padding: 7px 6px 6px 6px;
  @extend %toolbar;

  &, > box.start, > box.end {
    border-spacing: $base_padding;
  }

  &:backdrop {
    background-color: $headerbar_bg_color;
    transition: background-color $backdrop_transition;

    > * {
      filter: opacity(.5);
      transition: filter $backdrop_transition;
    }
  }
}

%actionbar-inline > revealer > box {
  background-color: transparent;
  color: inherit;
  box-shadow: none;
  padding-top: $base_padding;

  &:backdrop {
    background-color: transparent;
    transition: none;

    > * {
      filter: none;
      transition: none;
    }
  }
}

%actionbar-shrunk > revealer > box {
  padding-top: $base_padding / 2;
  padding-bottom: $base_padding / 2;
}

/*************
 * AdwBanner *
 *************/
banner > revealer > widget {
  /* There are 2 more instances in _sidebars.css, keep in sync with that */
  background-color: gtkmix($accent_bg_color, $window_bg_color, 30%);
  color: $window_fg_color;
  padding: $base_padding;

  &:backdrop {
    background-color: gtkmix($accent_bg_color, $window_bg_color, 15%);
    transition: background-color $backdrop_transition;

    > label, > button {
      filter: opacity(.5);
      transition: filter $backdrop_transition;
    }
  }
}

/******************
 * AdwToolbarView *
 ******************/
toolbarview {
  > .top-bar,
  > .bottom-bar {
    headerbar { @extend %headerbar-inline; }
    searchbar { @extend %searchbar-inline; }
    actionbar { @extend %actionbar-inline; }
    menubar   { @extend %menubar-inline; }
    tabbar    { @extend %tabbar-inline; }

    .collapse-spacing {
      padding-top: $base_padding / 2;
      padding-bottom: $base_padding / 2;

      headerbar { @extend %headerbar-shrunk; }
      searchbar { @extend %searchbar-shrunk; }
      actionbar { @extend %actionbar-shrunk; }
      menubar   { @extend %menubar-shrunk; }
      .toolbar  { @extend %toolbar-shrunk; }
      tabbar    { @extend %tabbar-shrunk; }

      viewswitcherbar { @extend %viewswitcherbar-shrunk; }
    }
  }

  &.undershoot-top    scrolledwindow { @include undershoot(top); }
  &.undershoot-bottom scrolledwindow { @include undershoot(bottom); }

  window.devel & > .top-bar {
    background-image: cross-fade(5% -gtk-recolor(url("assets/devel-symbolic.svg")),
                                 image(transparent));
    background-repeat: repeat-x;
  }

  window.devel dialog & > .top-bar {
    background-image: unset;
    background-repeat: unset;
  }

  > .top-bar,
  > .bottom-bar {
    background-color: $headerbar_backdrop_color;
    color: $headerbar_fg_color;

    &:backdrop {
      background-color: $headerbar_bg_color;
      transition: background-color $backdrop_transition;

      > windowhandle {
        filter: opacity(.5);
        transition: filter $backdrop_transition;
      }
    }
  }

  > .top-bar {
    box-shadow: 0 1px $border_color;

    &.border {
      box-shadow: 0 1px $border_color;
    }
  }

  > .bottom-bar {
    box-shadow: 0 -1px $border_color;

    &.border {
      box-shadow: 0 -1px $border_color;
    }
  }

  .sidebar-pane &,
  .content-pane &,
  .about & { // reset
    > .top-bar,
    > .bottom-bar {
      box-shadow: none;

      &, &:backdrop {
        background-color: transparent;
      }
    }
  }
}