Presentation-independent semantic authoring of content

A content author marks content semantically, rather than providing presentational indications in the content. The markings conform to a semantic schema, which define different semantic elements which may occur in the content. The resulting semantically-marked content is optionally combined with other semantically-marked content to form combined semantically-marked content. The final presentationally-marked content is transformed with a presentation transform indicating how semantic content should be displayed. The result is presentation data. The presentation data contains the content with presentational indications, including presentational markings or code references or fragments. These presentational indications indicate how content should be displayed. In this way, uniformity in presenting data authored by different content authors or at different times can be achieved.