style.css

html {
  font-size: 62.5% !important;
}

body {
  color: #222222;
  font-size: 1.6em; // this set default font size to 16px
  font-weight: 400;
  line-height: 1.6;
}

h1 {
	margin-bottom: 5rem;
}

h2,
h3,
h4,
h5,
h6 {
  margin-top: 0;
  margin-bottom: 2rem;
}

h1 {
  font-size: 3rem;
  line-height: 1.2;
}

h2 {
  font-size: 2.2rem;
  line-height: 28px;
  margin-top: 6rem;
}

h3 {
  font-size: 1.8rem;
  line-height: 24px;
}

h4 {
  font-size: 1.6rem;
  line-height: 1.35;
}

h5 {
  font-size: 1.8rem;
  line-height: 1.5;
}

h6 {
  font-size: 1.5rem;
  line-height: 1.6;
}