cPanel offers multiple themes for you to personalize your experience, providing a way to customize your dashboard. The most straightforward analogy to approach an explanation of this follows:
cPanel and WHM are the chassis, engine, brakes, and suspension that make your hosting interface work. A theme is the paint, hubcaps, and cute bumper sticker that covers the body of the application.
Themes can be customized and even created using HTML and CSS. While they retain functionality, themes provide you with the ability to adjust the look of cPanel to your liking.
cPanel's current default theme is called Basic. If you are interested in using the old theme, you can switch back to Retro.
cPanel Theme / Style Selection
You can change your theme in two ways. Either from the preferences section of your dashboard or by clicking your account profile drop-down at the top right of the page (where your username is), as shown below.
Next, select Change Style
From the following page, you can choose the style or theme you would like to use.