Looks like you need to learn more the technologies itself rather to post sublime issues: please make sure that you did all right on your side and that is the sublime problem.
Try this:
body {
background-color: #f4f4f4;
}
Also use preformatted text function to post your code: to make it better readable to others (if you post to others and not for yourself).
Also CSS is the technology that works in web browser, not in Sublime Text editor. Sublime Text is for pretty comfortable way to edit almost any code, so the topic title is meaningless.
Also this is the forum to post Sublime Text related stuff, please do not post here the stuff which is not correlated to Sublime Text.
For example, if you post somewhat not related to Arch Linux on Arch Linux forum you will be banned w/ msg ARCH only! (I was banned in that way and I think it is good to keep forum clean w/o off-topic stuff.
Wish you an interesting time to learn HTML, CSS technologies!