It is not that hard to make it looks exactly the same. Just doing a "save page as" in most browsers will automatically store all the html, css, and images neede

It is not that hard to make it looks exactly the same. Just doing a "save page as" in most browsers will automatically store all the html, css, and images needed to render a page to your hard drive. The only reason you noticed the different buttons and different text is cause the author decided to save himself some time and just replaced the page with a screenshot of how gmail is rendered on their computer.