[CSS] Collapsing Margins
Refactor the spacing between <header>, <article>, and <aside> so that elements will have a 20px margin above and below, regardless of their order on the page. Account for collapsing margins and use shorthand syntax.
header, article, aside { margin: 20px 0; }
Add a 20px bottom margin to <header>, <article>, and <aside> using the shorthand syntax. Remove any top margins and keep in mind that with top and bottom padding, the margins will no longer collapse.
header, article, aside { padding: 10px; } article { margin: 20px 0; } ---> Change to-----> header, article, aside { padding: 10px; margin: 0 0 20px 0; }