In fact, Google also has a page where it tells you why Google has changed the look of sign-in page. Here's the page of the reasons why it has changed. Whenever you are entering a new page which also arises you doubts, make sure that you check again that you are typing the correct url for the site you are opening. Then check whether the sign-in page of the site has a "LOCK" icon in the address bar, just on the left of your url. When you see this "LOCK" icon on Google Chrome, it means you are on a secure page. Google suggests that you use Google Chrome for browsing.