In software design, the look and feel of a graphical user interface comprises aspects of its design, including elements such as colors, shapes, layout, and typefaces (the "look"), as well as the behavior of dynamic elements such as buttons, boxes, and menus (the "feel"). The term can also refer to aspects of a non-graphical user interface (such as a command-line interface), as well as to aspects of an API – mostly to parts of an API that are not related to its functional properties. The term is used in reference to both software and websites. Look and feel applies to other products. In documentation, for example, it refers to the graphical layout (document size, color, font, etc.) and the writing style. In the context of equipment, it refers to consistency in controls and displays across a product line. Look and feel in operating system user interfaces serves two general purposes. First, it provides branding, helping to identify a set of products from one company. Second, it increases ease of use, since users will become familiar with how one product functions (looks, reads, etc.) and can translate their experience to other products with the same look and feel. In widget toolkits Contrary to operating system user interfaces, for which look and feel is a part of the product identification, widget toolkits often allow users to specialize their application look and feel, by deriving the default look and feel of the toolkit, or by completely defining their own. This specialization can go from skinning (that only deals with the look, or visual appearance of the graphical control elements) to completely specializing the way the user interacts with the software (that is, the feel). The definition of the look and feel to associate with the application is often done at initialization, but some Widget toolkits, such as the Swing widget toolkit that is part of the Java API, allow users to change the look and feel at runtime (see Pluggable look and feel). Some examples of Widget toolkits that support setting a specialized look and feel are: XUL (XML User Interface Language): The look and feel of the user interface can be specialized in a CSS file associated with the XUL definition files. Properties that can be specialized from the default are, for example, background or foreground colors of widgets, fonts, size of widgets, and so on. Swing supports specializing the look and