Summary

• Preserve real newline text nodes between rendered code lines in blog <pre><code> blocks.
• Add standard language-* classes on generated <code> tags.
• Move visible line numbers to CSS counters so extractor-visible code text contains only source code.

Why

The deployed agent-runtime article rendered code blocks as line spans without newline text nodes. Many HTML extractors, including OpenViking's HTML-to-Markdown path, saw a single flattened line instead of a multi-line code block.

Validation

• npm run build
• Verified generated blog/dist/post/agent-runtime/index.html has real newlines in the 0_run_claude.js <code> block.
• Verified OpenViking HTMLParser._html_to_markdown(...) converts the target snippet into a fenced multi-line block.
• Captured local headless Chrome screenshot to confirm visual line numbers still render.

Notes

• Best-practice reference: keep code samples semantic as <pre><code>…</code></pre>, with real whitespace/newlines in the DOM; use CSS for presentation-only line numbers.