Is it safe to login my gmail account while using HotSpot Shield?

Is it safe to login my gmail account, while using HotSpot Shield?

HTTPS (and the underlying SSL/TLS really) is specifically designed to be used in open environments, where everything is considered suspect, like public wifi networks. Generally speaking, anything that is transmitted over HTTPS is fairly secure as long as you trust the certificate. Sites like GMail that are entirely made in HTTPS now are safe because of this even on public networks, but sevenforums (among many others of course) for example is the hacker heaven for being over plaintext HTTP.

You must carefully check that you're entering, in fact, to GMail and not somewhere else. First off, look at the browser URL. Does it explicitly says "https"? Does it reads the full google.com domain? Then look at the site certificate, usually found in the padlock or similar icon. Look at it carefully, see who signed it and make sure it's emitted to google.com and that the root authority is in fact real. Don't ignore browser warnings about this! They're there for a good reason.
At that point, you can be fairly safe that you're really talking to the real GMail server and the entire connection is encrypted, at that point only it's safe to write your password.
Additionally, if you're using a public computer, you should also watch out for keyloggers and other local threats.

Have a look here for more details: tls - Is visiting HTTPS websites on a public hotspot secure? - Information Security Stack Exchange