Utilize two different div elements: one matching the width and height of the larger section, and another forming a square with side length equivalent to the diameter of the semicircle.
Ensure that both divs have a black background color.
The larger section should have rounded corners, approximately 10% for the top corners and 0% for the bottom corners - feel free to adjust as needed.
The semicircle is actually a full circle, with a border radius of 50%. It should be positioned absolutely within the larger section.
Note that using border radius may sometimes result in a slightly jagged appearance. In such cases, consider utilizing SVG instead of HTML and CSS as per your query.
To ensure flexibility in size and position, use percentages for dimensions and positioning so the design can adapt accordingly.