while opening "https://www.flipkart.com/" a window opens for login. How to handle this window in selenium? :     System.setProperty("webdriver.gecko.driver", 
    "F:\\Software_Sel\\GekoDriver\\geckodriver-v0.16.1-win64\\geckodriver.exe");
    WebDriver wd = new FirefoxDriver();
	wd.get("https://www.flipkart.com/")						
	WebElement e1= wd.findElement(By.className("_2AkmmA _29YdH8")); 
    e1.click();

I have also tried iframe. But cant handle.Kindly help.