Uses markdown-it-anchor to generate linkable IDs on h2-h4 headings.
Headings become clickable links with a subtle # indicator on hover.
Includes scroll-margin-top so anchored headings don't hide behind
the sticky header.
Integrates @11ty/eleventy-plugin-syntaxhighlight (PrismJS) for
build-time syntax highlighting of fenced code blocks. Includes
a custom GitHub-inspired theme with dark mode support (.dark class).
All existing articles with triple-backtick code blocks will
automatically get highlighting on next Eleventy rebuild.
Also fixes overflow-x: hidden on .prose/.e-content that was
clipping scrollable code blocks — changed to overflow-x: clip.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>