1. Give section "wrapper" a 700 pixel width and center it. Hint. The section is a block element, so text-align: center; does not work.
2. Add a 3 pixel grey border on the bottom of the header tag.
3. Display the menu horizontally across the page.
4. Kill the padding on the unordered list inside the navigation.
5. Remove the underline from the links and color them white. Color background a dark color.
6. Give links a 10 pixel margins, 10px 20px padding and set their display to inline-block.
7. Style the background of the hover green.
8.The left and right columns are to be exactly 150 pixels wide. Color the background "silver".
9. The center column is to be 400 pixels wide and the background is colored #ddd;.
10. Using floats, position the three content boxes so that the web page is a 3 column layout.
11. Add 20 pixel padding to all columns. Hint. All columns are divs.
Make the float layout responsive.
1. Display the navigation list items as blocks and remove margins.
2. Set the width of the navigation links to 100% and center the text.
3. When the screen goes below 700 pixels engage media queries — @media screen and (max-width: 700px) {}
4. Make column width 100%. This stacks the floats.
5. Add 10 pixel padding to the sides of all section elements.