Cascading Style Sheets

What Hacker News says

1. omnicognateNov 2013
   Hi, I wrote this article (the response, not the original). though I didn't post it here - I just noticed the pingback email.

   I am indeed responding mainly to the wording, and you'll see at the start and end of the article statements that I think the original author does at least kind of understand what is going on (though I don't think his understanding is very solid).

   Your statement that 'the css unit "px" has no relationship to the actual size of a pixel on the screen' exemplifies why I am concerned about the wording and thought it necessary to write a response. This statement is just not true!

   The CSS px unit was carefully designed to embody as closely as possible the intuitive concept of a "monitor pixel", while retaining sufficient flexibility to allow implementors to accommodate a wide range of devices. The whole concept of unit anchoring was invented to support this. To pretend the px unit has no relationship to actual pixels is to waste all of this work.(*)

   I would suggest people aim for one of two levels of understanding:

   1. Really understand the rules. Read the standard, and/or a proper CSS book like "Cascading Style Sheets: The Definitive Guide" by Eric Meyer. Be an expert and design with confidence.

   2. Altenatively, just think of 1px as a monitor pixel. The standards authors put a lot of effort in to allow people to do so.

   For people that are currently in state 2 and are uneasy about retina displays, printers and the rest, my advice would be that they are going to need to go to state 1. It's not that hard. Just getting a vague idea (as many people are) that "px" is angular, or worse that it's in some way "unreliable", is not going to help anyone.

   [PS. Here's an ironic aside about the lengths people have gone to to make 1px correspond as closely as possible to a real pixel: As you say, 'marking a button as "width: 1cm" will almost never render something over 1cm of the screen geometry'. But why exactly is this? It's because the whole system of units has been anchored to the screen pixel size (or a simple multiple or fraction of it). On a printer, where there is no "pixel" worth anchoring to, the units are typically anchored to physical units, and width: 1cm really does mean 1cm. The reason that on your monitor screen 1cm is not 1 real cm is because your browser is resizing everything - it's bending over backwards to make 1px match the screen pixel size! (or a simple multiple or fraction yadda yadda yadda...)]

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2. willwagnerApr 2009
   I think you mean Eric Meyer and the book Cascading Style Sheets, The Definitive Guide (http://meyerweb.com/eric/books/css-tdg/). I really like this book and highly recommmend it.

   It hasn't converted me into a CSS fanatic, but it has helped me learn the tech and write better CSS when needed.

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