html {
  font-size: 62.5%; /* sets the base font to 10px for easier math */
}
 
body {
  font-size: 16px;
  font-size: 1.6rem;  
  /* sets the default sizing to make sure nothing is actually 10px */
}
 
h1 {
  font-size: 32px;
  font-size: 3.2rem;
}