paper-gtk-theme/Paper/gtk-3.0/widgets/_granite.scss

/************
 * Popovers *
 ************/

GraniteWidgetsPopOver {

  -GraniteWidgetsPopOver-arrow-width: 21;
  -GraniteWidgetsPopOver-arrow-height: 10;
  -GraniteWidgetsPopOver-border-radius: 8px;
  -GraniteWidgetsPopOver-border-width: 0;
  -GraniteWidgetsPopOver-shadow-size: 12;
  
  border: 1px solid $base_color;
  background: $base_color;
  color: $fg_color;

  .button {
    background-image: none;
    background: none;
    border: none;

    &:active,
    &:active:hover, {
      color: $selected_bg_color;
    }
  }

  > .frame {
    border:none;
  }

  .sidebar.view {
    border: none;
    background: none;
  }
}

GraniteWidgetsStaticNotebook .frame {
  border: none;
}

.popover_bg {
  background-color: $base_color;
  background-image: none;
  border: 1px solid $base_color;
  color: $fg_color;
}


/***********
 * Welcome *
 **********/

GraniteWidgetsWelcome {
  background-color: $base_color;

  GtkLabel {
    color: $fg_color;
  }

  .h1,.h3 {
    color: transparentize($fg_color, 0.2);
  }
}

/**************
* Source List *
***************/

.source-list {
  -GtkTreeView-horizontal-separator: 1px;
  -GtkTreeView-vertical-separator: 6px;

  background-color: $bg_color;
  border: solid $borders_color;
  color: $fg_color;
  border-right-width: 1px;

  &:backdrop {}

  .category-expander {
    color: transparent;
  }

  .badge {
    background-image: none;
    background-color: transparentize(black, 0.6);
    color: $bg_color;
    border-radius: 10px;
    padding: 0 6px;
    margin: 0 3px;
    border-width: 0;

    &:selected:backdrop,
    &:selected:hover:backdrop {
      background-color: transparentize(black, 0.8);
      color: shade ($bg_color, 0.95);
    }
  }

  row,
  .list-row {
    border:none;
    padding: 0;

    > GtkLabel,
    > label {
      padding-left: 6px;
      padding-right: 6px;
    }
  }
}


/**************
* Storage Bar *
**************/
.storage-bar {

  .trough {
    border: none;
    box-shadow:0 1px 0 0 $bottom_highlight;
    background-image: none;
    background-color: transparent;
    padding: 8px 6px;
  }

  .fill-block {
    background-color: $yellow;
    border:none;
    box-shadow: inset 0 1px 0 0 transparentize(black, 0.9), inset 0 -1px 0 0 transparentize(black, 0.9);

    transition: all 200ms ease-in-out;

    padding: 8px 6px;
  
    &:first-child {
      border-top-left-radius: 4px;
      border-bottom-left-radius: 4px;
      border-left-width: 1px;
      box-shadow: inset 0 1px 0 0 transparentize(black, 0.9),
                  inset 1px 0 0 transparentize(black, 0.9),
                  inset 0 -1px 0 0 transparentize(black, 0.9);
    }
    
    &:last-child {
      border-top-right-radius: 4px;
      border-bottom-right-radius: 4px;
      box-shadow: inset 0 1px 0 0 transparentize(black, 0.9),
                  inset -1px 0 0 transparentize(black, 0.9),
                  inset 0 -1px 0 0 transparentize(black, 0.9);
    }

    &.empty-block {
      background-color: $base_color;
    }
    
    &.app {
      background-color: $blue;
    }

    &.audio {
      background-color: $orange;
    }

    &.photo {
      background-color: $red;
    }

    &.video {
      background-color: $purple;
    }

    .legend {
      padding: 12px;
      border-radius: 4px;
    }
  }
}