When a relative line-height is inherited, it is not relative to the element's font-size. Why? And how do i make it relative?

I have a global reset that sets font-size and line-height to inherit for every element:

* {
  font-size:   inherit;
  line-height: iherit; }

For html, i define them explicitly:

html {
  font-size:   16px;
  line-height: 1.25em; } /* 16×1.25 = 20 */

Note, that line-height is set in a relative unit.

For h1, i define different font-size:

h1 {
  font-size: 4em; }

I expect h1 to inherit the relative line-height of 1.25em. The resulting line-height should be equal to 80px (16×4×1.25).

But in reality h1's line-height remains equal to 20px (that's the same as html's: 16×1.25=20).

Say, i have the following HTML:

<p>foo<br>bar</p>
<h1>foo<br>bar</h1>

Screenshot of the result:

http://jsfiddle.net/M3t5y/5/

To work around this problem, i have to define h1's line-height explicitly equal to the same value that it inherits:

h1 {
  font-size:   4em;
  line-height: 1.25em; }

Then line-height becomes correct:

http://jsfiddle.net/M3t5y/6/

It looks like the relative value is first calculated into the absolute value and then the absolute value is inherited. Or maybe it is inherited relative to the parent