Unity is created when elements that support each other all work together toward a common goal. Creating unity in your design helps avoid sending mixed messages to the user and reduces cognitive overload. Your design elements should look like they belong together and not randomly placed on the page. Unity gives a sense of oneness to a visual image and gives the design a theme. This is not only applicable to visual images but also text. The text can support the image and vise versa. Source
Unity: Source
Unity: Online
Unity: Real life
