gnome-shell-dark-theme/gnome-shell-sass/widgets/_misc.scss

// Rubberband for select-area screenshots
.select-area-rubberband {
  background-color: st-transparentize(-st-accent-color,0.7);
  border: 1px solid -st-accent-color;
}

// User icon
.user-icon {
  background-size: contain;
  border-radius: $forced_circular_radius;
  icon-size: $base_icon_size * 4;

  background-color: transparentize($osd_fg_color,0.95);
  color: $osd_fg_color;

  & StIcon {
    padding: $base_padding * 2;
  }

  &.user-avatar {
    box-shadow:inset 0 0 0 1px transparentize($osd_fg_color, 0.9);

    @if $contrast == 'high' {
      @include draw_hc_inset();
    }
  }
}

.lightbox { background-color: black; }
.flashspot { background-color: white; }

// Hidden
.hidden { color: transparent;}

// Caps-lock warning
.caps-lock-warning-label {
  text-align: center;
  padding-bottom: 8px;
  @extend %caption;
  color: $warning_color;
}

/* Workspace animation */

.workspace-animation {
  background-color: $system_bg_color;
}

/* Tiled window previews */
.tile-preview {
  background-color: st-transparentize(-st-accent-color,0.5);
  border: 1px solid -st-accent-color;
}