Misleading font sizing

On several occasions in recent weeks, I've come across people taking about css font sizing and the 62.5% trick.

They talk about setting the body font size to 62.5% and there after using ems on the basis that 1em will equal 10px and you can then make easy adjustments for your diferent font size requirements.

The problem is they talk about the concept as if it's a solution cast in bronze.

What they don't tell you is that when the idea was first conceived, it was based on the assumption that the browsers default font size would be set to 16px.

It isn't on my browsers, and I suspect many others, so your site's fonts will look nothing like what you intended.

I strongly recommend that you assume the end user has set their browser to suit them.

On this basis, make the default font-size for your layout, typically set for the body element, 1em. Inherit this for the default p size and go up for h elements and down for less important text, menus, etc.