The same "look and feel" as what? Maintaining a consistent look and feel of a web site can be easy, depending on how the site is built. Indeed, that is one reason for segregating the style (CSS) from the content (HTML). This allows the same CSS to be used on a whole site, instead of page by page.
A further development of the concept is the use of PHP include files. These allow common page elements like headers, footers and navigation to be written once and used on all (or a group of) pages.
However, I'm not sure that is what you mean. If by the "same look and feel" you mean the same as another site, that is quite different. The look and feel of a site can be and is copyright. So if you make an exact copy of the look and feel of, say, a particular car manufacturer's site, they can have your site taken down.
But if you make a site that is nearly the same look and feel, but not quite, that can be different. However, like I said, I'm not sure that is what you meant...
P.S. I've moved the thread to the CSS forum, because look and feel is style, not content.