src/vs/platform/theme/common/themeService.ts/getThemeTypeSelector
export function getThemeTypeSelector(type: ColorScheme): string {
	switch (type) {
		case ColorScheme.DARK: return 'vs-dark';
		case ColorScheme.HIGH_CONTRAST_DARK: return 'hc-black';
		case ColorScheme.HIGH_CONTRAST_LIGHT: return 'hc-light';
		default: return 'vs';
	}
}