We'll now do some math – or better than that, we're going to let Sass do the math for us:
$s: $font-size*$scale; $r: $font-size; $l: $r/$scale; $xl: $l/$scale; $xxl: $xl/$scale; $xxxl: $xxl/$scale;
I personally labeled the base font as Regular, you can name it as you please – and the following sizes are made by simple multiplication/division for our scale factor.
Using the 16px base we're going to obtain the following values:
12, 16, 21, 28, 37, 50, 67
Yes, the H1, for example, is too big – but it doesn't really matter right now, you'll be able to change it in a heartbeat.
Now, how can you use it?
Simple enough, you just have to do one simple declaration – or more, based on the number...