"Sanity-ize" REMs by setting them to 10px-baseline aka "Tiny Happy Pixels Dancing."

reset-rems

/* this is the "root" in "root em." */
html {
  font-size: 62.5%; /* Now 10px = 1rem! */
}

body {
  font-size: 16px; /* px fallback */
  font-size: 1.6rem; /* default font-size for document */
  line-height: 1.5; /* a nice line-height */
}

/* for everything else, rem = px/10 */
footer {
  font-size: 13px;
  font-size: 1.3rem;
}

/* you can safely nest rems, it's still 1rem = 10px */
footer small {
  font-size: 10px;
  font-size: 1rem;
}