rowid,title,contents,year,author,author_slug,published,url,topic
330,An Explanation of Ems,"Ems are so-called because they are thought to approximate the size of an uppercase letter M (and so are pronounced emm), although 1em is actually significantly larger than this. The typographer Robert Bringhurst describes the em thus:


	The em is a sliding measure. One em is a distance equal to the type size. In 6 point type, an em is 6 points; in 12 point type an em is 12 points and in 60 point type an em is 60 points. Thus a one em space is proportionately the same in any size.


To illustrate this principle in terms of CSS, consider these styles:

#box1 {
     font-size: 12px;
     width: 1em;
     height: 1em;
     border:1px solid black;
}

#box2 {
     font-size: 60px;
     width: 1em;
     height: 1em;
     border: 1px solid black;
}

These styles will render like:

 M

and

 M

Note that both boxes have a height and width of 1em but because they have different font sizes, one box is bigger than the other. Box 1 has a font-size of 12px so its width and height is also 12px; similarly the text of box 2 is set to 60px and so its width and height are also 60px.",2005,Richard Rutter,richardrutter,2005-12-02T00:00:00+00:00,https://24ways.org/2005/an-explanation-of-ems/,design