Typography readability optimization & weight info

readability.css

/*
100 = thin
200 = extra-light
300 = light
400 = normal, book
500 = medium
600 = demi-bold
700 = bold
800 = heavy
900 = black
*/
html {
  color: #111;
  background: #FFFEF0;
  font-family: sans-serif;
  font-size: 16px;
  line-height: 1.618em;
  max-width:35em; /* 35-60em */
  text-rendering: optimizeLegibility;
}

h1,h2,h3,h4,h5,h6 {
  font-family: serif;
}

p {
  margin: 0.8125em 0;
}