src/vs/editor/standalone/browser/standaloneThemeService.ts/StandaloneThemeService/_onOSSchemeChanged
class StandaloneThemeService:	private _onOSSchemeChanged() {
		if (this._autoDetectHighContrast) {
			const wantsHighContrast = window.matchMedia(`(forced-colors: active)`).matches;
			if (wantsHighContrast !== isHighContrast(this._theme.type)) {
				// switch to high contrast or non-high contrast but stick to dark or light
				let newThemeName;
				if (isDark(this._theme.type)) {
					newThemeName = wantsHighContrast ? HC_BLACK_THEME_NAME : VS_DARK_THEME_NAME;
				} else {
					newThemeName = wantsHighContrast ? HC_LIGHT_THEME_NAME : VS_LIGHT_THEME_NAME;
				}
				this._updateActualTheme(this._knownThemes.get(newThemeName));
			}
		}
	}