header, footer {
  border-radius: 2em;
  box-shadow: 10px 10px 10px black;
}

aside {
  width: 20%
}

section {
  width: 70%
}

header {
  height: 5em;
  background-color: #ff00ea;
   padding: 1em;
}

nav {
  margin: 1em;
  height: 2em;
  background-color: #abe4e0;
  text-align: center;
}

nav a {
  margin-right: 2em
}

aside, section {
  height: 400px;
  float: left;
  margin-left: 1.5%;
  margin-right: 1.5%;
  padding-left: 1%;
  padding-right: 1%;
  padding-top: 1em;
  margin-top: 2em;
  margin-bottom: 2em;
  background-color: lightblue;
}

footer {
  text-align: center;
  clear: both;
  background-color: lime;
  height: 2em;
}