[RbnJrg]

Originally Posted by JSWolf

h1 is 2em by default. 200% would be 4em.

Not at all. I see you didn't test what I wrote; do the try and you'll see that your statement is wrong. A font-size of 200% for h1 is exactly the same as a font-size of 2em.

EDIT: Here you have an epub so your tests will be easier. And here you can also watch an screenshot:



with

.percent {
   font-size: 400%;
}

.ems {
   font-size: 4em;
}

and

<h1 class="percent">TITLE in %</h1>

<h1 class="ems">TITLE in ems</h1>