* { margin: 0; padding: 0; } .wrapper { width: 100%; border: 8px solid red; box-sizing: border-box; display: flex; flex-flow: column nowrap; align-items: center; } header, section, article, footer { width: 600px; } header { height: 50px; background-color: mediumslateblue; } section { height:100px; background-color: midnightblue; } article { height: 100px; background-color: cornflowerblue; } .foo..