我在更改 Google 的 Material Design 主题的默认颜色时遇到问题。主要和次要颜色已更改，但背景和表面颜色没有更改。我已在此处附上我的代码以供参考。任何线索将不胜感激。提前致谢。
@import "colors";
$mdc-theme-primary: $primary;
$mdc-theme-on-primary: if(mdc-theme-contrast-tone($mdc-theme-primary) == "dark", $dark, $light);
$mdc-theme-secondary: $secondary;
$mdc-theme-on-secondary: if(mdc-theme-contrast-tone($mdc-theme-secondary) == "dark", $dark, $light);
$mdc-theme-background: $dark;
$mdc-theme-surface: scale-color($dark, $lightness: 5%);
$mdc-theme-on-surface: if(mdc-theme-contrast-tone($mdc-theme-secondary) == "dark", $dark, $light);
$mdc-theme-error: $red;
$mdc-theme-on-error: if(mdc-theme-contrast-tone($mdc-theme-secondary) == "dark", $dark, $light);
@import "@material/theme/mdc-theme";