src/vs/workbench/common/theme.ts/WORKBENCH_BACKGROUND
export function WORKBENCH_BACKGROUND(theme: IColorTheme): Color {
	switch (theme.type) {
		case ColorScheme.LIGHT:
			return Color.fromHex('#F3F3F3');
		case ColorScheme.HIGH_CONTRAST_LIGHT:
			return Color.fromHex('#FFFFFF');
		case ColorScheme.HIGH_CONTRAST_DARK:
			return Color.fromHex('#000000');
		default:
			return Color.fromHex('#252526');
	}
}