7) What does * { box-sizing: border-box; } do? What are its advantages?

It makes every element in the document include the padding and border in the element’s inner dimension for the height and width computation. In box-sizing: border-box, The height of an element is now calculated by the content’s height + vertical padding + vertical border width.

The width of an element is now calculated by the content’s width + horizontal padding + horizontal border width.