How to set H1 and other within CSS?

[toplisek]

How to set H1 and other within CSS?
I have all ratio defined for all elements like Hi1, H2...
How to add correct start size as elements have defined
em {
font-style: normal;
}

h1{
font-size: 39px;
font-weight: normal;
}

h2{
font-size: 20px;
font-weight: bold;
}

- Is there any correct option to define basic value in % to lower H1 and H2 as ratio is defined per all elements?
- If I define font-size : 63 %; within body element will be all elements according lower or I have to change px to % for each element?
- What would be base for this to change?
- How to change than em value for each element not using px?

[Fang]

http://www.w3.org/TR/CSS2/sample.html

[rnd me]

% cascades.

body {font-size: 50%;}
div {font-size: 50%;}

would render divs at 25% of the page's default font size. (0.5 X 0.5)