*,html{
  margin: 0;
  padding: 0;
}
body{
  font-family: Helvetica, Arial, sans-serif;
  font-size: 1em;
}
header{
  display: -webkit-flex;
  display: flex;
  justify-content: space-between;
}
h1{
  padding: 20px;
}
span{
  margin: auto 40px;
  color: gray
}
span a{
  color: black;
  text-decoration: none;
}
span a:hover{
  text-decoration: underline;
}
main{
  margin: 40px;
}
h2{
  margin-bottom: 10px;
  border-bottom: 1px solid gray;
  font-size: 2em;
  font-weight: lighter;
}