Exercise: Building a Webpage Layout Using the HTML Box Model

In this exercise, you will create a fully structured webpage that incorporates the key elements of the HTML box model. Your task is to design a layout that includes a header, a sidebar, a main content area, and a footer. Each section should be clearly defined and styled using the box model properties (margin, border, padding, and content) to ensure proper spacing and alignment. Additionally, the layout should be responsive, adapting seamlessly to different screen sizes. This exercise will help you understand the practical application of the box model in creating well-organized and visually appealing web pages.