Description: In this code, React and CSS are used to design a circular-shaped div element. The basic styles are defined using CSS in the classes identified as ".App," ".app," and "body" in the associated style file. The font family and text alignment are set using the "font-family" and "text-align" properties. The background color, text color, and border radius are set to make the element circular using the CSS properties associated with ".app". The width of the element is set to be 50% of the original element's width, and a smooth transition effect is applied during transformations using the "transition" property. A shadow effect is defined for the element when the cursor hovers over it using the "box-shadow" property, and the text color changes to the blue color associated with the hovered element. The background color of the main page is set to a dark gray color using the "background-color" property associated with "body". A "div" element is used inside the "center" element to center the div element on the main page.