Problem
Pages with a subtitle in front matter (f.e. article/fonts) fail W3C validation:
the template renders <h3 class="subtitle"> immediately after
<h1>, skipping <h2>. This also makes screen readers announce
the subtitle as a level-3 heading, which it is not.
Changes
- layouts/articles/list.html and single.html: render subtitle as <p class="subtitle"> instead of <h3 class="subtitle">.
- documentation.scss: add .subtitle styles (size, weight, italic, muted color, margins) to preserve the existing look. Subtitle does not have horizontal line now as it is not header now, but it is easy to add in style.
Rationale
subtitle is part of the title block (alongside title, authors,
copyright, trademarks), not a section heading. It should not
participate in the document heading hierarchy. Visual appearance is
now controlled via CSS instead of borrowing <h3> defaults.