1- What is the box model? it's a box thw wrap every elemnt in HTML.

2- What is the difference between margin and padding? the margin is the space outside the border and the padding is the space inside the border.

3- What is the purpose of the box-sizing CSS property? box sizing is allow us to count the padding and the border with the total height and width of the element.

4- What does the outline property do? it's a line outside the border and its not count any space.

5- How do you add a background image in CSS? the property is background-image and the value is URL.

6- Given a div with a width of 200px, margin of 20px and padding of 20px, what is the calculated width by the browser? 240px.

7- Given a div with a height of 100px, border of 10px and padding of 20px, what is the calculated height by the browser? 160px.

8- What does margin:auto do? we can center the element with margin auto it will split the space between right and left.