Jim Rudolf wrote:
> Why not use the unit of 'px' in your CSS declarations?
Simple: because defining absolute point size is [usually] bad.
I've come to realize that there's a blurry but important
line between chaos and control when it comes to delivering
a good web experience to a broad base of users. Some people
say that the designer should give total freedom to the user,
and I couldn't agree less. Others say that the designer should
be able to define what the user sees to the pixel. That's not
as bad, but it's still deeply misguided, simply because you
should take advantage of the user's ability to [partially]
determine the display settings.
The best way is the middle. So, in this case, you want
to be able to show MacOS users slightly larger text in
terms of "point size" than Windows users (because the dpi
discrepancy can ruin your design), but you don't do that
by defining exactly how many pixels the text should be.
This, because you don't know the environment of the user,
and he does: his monitor size, his resolution, his eyesight,
his desk, etc. The user can help you improve (customize)
your design on his end; you ignore such a valuable
opportunity at your own peril.
The trick is drawing the line in the right place. For example,
I believe it should be difficult (but not impossible) for a
user to decide what typeface to see a design in. Why? Because:
1. It reduces the participation of the designer. And if we
assume that creative freedom is important, that's bad.
2. The user -not being a typographer- is generally not qualified
to determine what's good. This has been shown again and again
in readabilty studies, BTW: that perception of merit has a
very weak correlation to actual merit. What the user can
and should do is convey the parameters of his environment,
so you can optimize.