The big factors you need to consider are screen size, and the fact that you're on a touch screen. (retina/ultra HD image optimization's important as well, but only to the aesthetic, it's not essential to interaction).
Android and iPhone's standards are great for advice in terms of usability with small touch screens. Things like minimum icon sizes are things that should be taken seriously.
However, you don't want to imitate the graphic elements of the operating system, because as DA01 mentions, that's deceptive. It can confuse the user as to where they are (they should remember that they're just hanging out in their browser) and how much access your site has over their device.
Touch screen, screen size, and of course, how people hold and use the device, are the big factors you need to concern yourself with while developing a mobile interface. No need to emulate the graphic style of one brand or another.