html {
  background-color: #deded8;
  font-family: trebuchet, geneva, verdana, sans-serif;
} 
body {
  margin: 0;
} 
article, aside, footer, header {
  padding: 0.5rem;
  box-sizing: border-box;
} 
header {
  background-color: #333;
  color: #ccc;
  text-align: center;
  border-bottom: 1px solid;
} 
aside {
  background-color: white;
} 

/* default navigation values */
nav {
  display: flex;
  flex-direction: column;
  background-color: black;
  padding: 10px 0;
} 
nav a {
  flex: auto;
  text-align: center;
  color: white;
  margin: 0 5px;
  padding: 5px 0;
  text-decoration: none;
  border-bottom: 1px solid #ccc;
} 
nav a:hover {
  outline: 1px solid red;
  color: red;
  text-decoration: underline;
} 


  /* larger screen */
@media screen and (min-width: 500px) {
  main {
    display: flex;
    box-sizing: border-box;
    border-bottom: 0.5rem solid;
  } 
  nav {
    order: -1;
    flex: 0 1 200px;
    min-width: 150px;
  } 
  article {
    flex: 1 2 600px;
  } 
  aside {
    flex: 0 1 200px;
    min-width: 150px;
  } 
}