only fill box background if a background-color was explicitly set

      margins[3]);

  /* draw background */

  {

  if (config.background) {

    const auto& bg_box = layout.content_box;

    FillStyle bg_fill;

    bg_fill.color = config.background_color;

    bg_fill.color = *config.background;

    fillRectangle(

        layer,

  config->color_scheme = env.color_scheme;

  config->text_color = env.text_color;

  config->border_color = env.border_color;

  config->background_color = env.background_color;

  config->scale_x = env.scale_x;

  config->scale_y = env.scale_y;

  config->scale_layout_x = env.scale_layout_x;

    {"scale-y-max", bind(&configure_float_opt, _1, &config->scale_y.max)},

    {"scale-y-padding", bind(&configure_float, _1, &config->scale_y.padding)},

    {"scale-y-layout", bind(&configure_scale_layout, _1, &config->scale_layout_y)},

    {"background-color", bind(&configure_color, _1, &config->background_color)},

    {"background-color", configure_color_opt(&config->background)},

    {

      "foreground-color",

      configure_multiprop({

  child_env.color_scheme = config->color_scheme;

  child_env.text_color = config->text_color;

  child_env.border_color = config->border_color;

  child_env.background_color = config->background_color;

  child_env.background_color = config->background.value_or(env.background_color);

  child_env.scale_x = config->scale_x;

  child_env.scale_y = config->scale_y;

  child_env.scale_layout_x = config->scale_layout_x;

  FontInfo font;

  Measure font_size;

  ColorScheme color_scheme;

  Color background_color;

  std::optional<Color> background;

  Color text_color;

  Color border_color;

  DomainConfig scale_x;