CSS-klasse for sperret tekst

[josteinaj]

Flyttet fra nlbdev/nordic-epub3-dtbook-migrator#335:

Letter-spacing is sometimes used to increase readability and for visual effect. In some cases it is also be used for emphasis, although it is not recommended for that use.

Norwegian braille has special rules for handling tracked text differently than italics and bold, and other braille standards might also. So it could be convenient to specify how tracked text should be marked up, even though I don't think this is a common occurence in books nowadays.

I think this maps best to the <i> element. From developer.mozilla.org:

The HTML <i> Element represents a range of text that is set off from the normal text for some reason, for example, technical terms, foreign language phrases, or fictional character thoughts. It is typically displayed in italic type.

Text tracking should not be combined with italics (for readability reasons), so if we use <i> then the default italics style should be reset.

For instance, this text:

The term   p r o s e   c o n t e n t   is defined above.

could be marked up as:

<p>The term <i class="spaced">prose content</i> is defined above.</p>

with the CSS:

.spaced {
    font-style: normal;
    letter-spacing: 0.5em;
    padding-left: 0.5em;
    padding-right: 0.5em;
}

[josteinaj]

@eliseaas er dette noe som bør inn i revisjon av retningslinjene?