static function filterDefaults( $defaults ) {

		// SASS => WP
		$overrides = [
			'examples-header-color' => 'edu_textbox_examples_header_color',
			'examples-header-background' => 'edu_textbox_examples_header_background',
			'examples-background' => 'edu_textbox_examples_background',
			'exercises-header-color' => 'edu_textbox_exercises_header_color',
			'exercises-header-background' => 'edu_textbox_exercises_header_background',
			'exercises-background' => 'edu_textbox_exercises_background',
			'learning-objectives-header-color' => 'edu_textbox_objectives_header_color',
			'learning-objectives-header-background' => 'edu_textbox_objectives_header_background',
			'learning-objectives-background' => 'edu_textbox_objectives_background',
			'key-takeaways-header-color' => 'edu_textbox_takeaways_header_color',
			'key-takeaways-header-background' => 'edu_textbox_takeaways_header_background',
			'key-takeaways-background' => 'edu_textbox_takeaways_background',
		];

		$transient_name = 'pressbooks_theme_options_global_parsed_sass_variables';
		$parsed_sass_variables = get_transient( $transient_name );
		if ( $parsed_sass_variables === false ) {
			// Order of files matter. If a variable is duplicated in other files then the last one takes precedence
			$parsed_sass_variables = [];
			$sass = Container::get( 'Sass' );
			$path_to_global = $sass->pathToGlobals();
			$path_to_theme = get_stylesheet_directory();
			$files = [
				$path_to_global . '/variables/_specials.scss',
				$path_to_theme . '/assets/styles/components/_specials.scss',
			];
			foreach ( $files as $file ) {
				if ( file_exists( $file ) ) {
					$parsed_sass_variables[] = $sass->parseVariables( \Pressbooks\Utility\get_contents( $file ) );
				}
			}
			set_transient( $transient_name, $parsed_sass_variables );
		}

		foreach ( $parsed_sass_variables as $parsed_variables ) {
			foreach ( $overrides as $sass_var => $wp_option ) {
				if ( isset( $parsed_variables[ $sass_var ] ) ) {
					if ( ! empty( $parsed_variables[ $sass_var ] ) ) {
						$defaults[ $wp_option ] = $parsed_variables[ $sass_var ]; // Override default with new value
					}
				}
			}
		}

		return $defaults;
	}