1.0   (16/24)  0.8125 (13/16)
1.618 (25/32)  1.315  (21/24)
2.618 (42/48)  2.127  (34/40)
4.236 (68/72)  3.442  (55/64)

<div>
  <h1 class="f7 mv">Font Size 7</h1>
  <h1 class="f6 mv">Font Size 6</h1>
  <h2 class="f5 mv">Font Size 5</h2>
  <h3 class="f4 mv">Font Size 4</h3>
  <h4 class="f3 mv">Font Size 3</h4>
  <h5 class="f2 mv">Font Size 2</h5>
  <h6 class="f1 mv">Font Size 1</h6>
  <p class="fs mv">Font Size Small</p>
</div>