The font size values aren't necessarily some calculation of mathematical perfection. It's entirely possible the authors tried a few values and thought "this looks good." Based on this article, it seems like they originally were using 14px @ 1:1.618, 44px @ 1:1.618 and rounding a lot, and eventually decided to just to use 18px
instead of 16.807
. Using a modular scale is nice, but breaking it isn't illegal.
To answer, your second question, the great thing about em
s is that they're relative! If you want to scale all of the type proportionally, just change the font-size on the body:
body {
font-size: 18px;
}
h1 {
font-size: 3em;
}
h2 {
font-size: 2em;
}
p {
font-size: 1em;
}
Since foundation does everything in ems, you won't need to edit any variables.