Styles a stretch of content within the flow of the surrounding text.
<span bold=true {important}> displays important in bold.<span size=24,pt color={navy} {Heading}> displays larger, navy text.<greeting:span {Hello}> creates a span that can be changed later, e.g. with <greeting {Goodbye}>.The content of the span: text, values and other presentation tags.
A span's content flows with the text around it: if it reaches the end of a line, it wraps onto the next line along with the surrounding text. A span has no box of its own unless it is given a border or a background colour.
Named spans are the usual way to display a value that changes, such as a score or a status message: create the span once, then assign new contents to it.