fabioc-aloha Markdown to HTML Conversion
Write in Markdown, share as a polished web page — zero dependencies for viewers
Convert Markdown documents into self-contained HTML files with embedded CSS, base64 images, and Mermaid diagram rendering. Ready for quick-share distribution, offline viewing, print, or email attachment.
When to Use
- Sharing formatted documents without requiring Word or PDF viewers
- Creating self-contained HTML pages for offline distribution
- Generating printable web pages from Markdown sources
- Quick previews of documentation with professional styling
- Email attachments that open in any browser
- Static site generation from Markdown sources
Supported Formatting
| Format | Status | Notes |
|---|---|---|
| Headings | ✅ | H1-H6 with styled colors |
| Bold/Italic | ✅ | Standard emphasis |
| Links | ✅ | Styled with underline on hover |
| Images | ✅ | Base64 embedded or linked |
| Code blocks | ✅ | Syntax highlighting, monospace font |
| Inline code | ✅ | Background highlight |
| Tables | ✅ | Striped rows, header styling |
| Blockquotes | ✅ | Left border, italic style |
| Lists | ✅ | Ordered, unordered, nested |
| Task lists | ✅ | Checkbox rendering |
| Mermaid diagrams | ✅ | PNG or table fallback |
| SVG | ✅ | Inline or base64 embedded |
| Horizontal rules | ✅ | Styled dividers |
| Footnotes | ✅ | Via pandoc |
| Math (KaTeX) | ⚠️ | Requires --katex flag |
Key Features
| Feature | Details |
|---|---|
| Style presets | professional, academic, minimal, dark |
| Self-contained | All CSS embedded in <style> block, no external deps |
| Image embedding | Local images converted to base64 data URIs |
| Mermaid support | PNG rendering or table fallback for diagrams |
| Print-ready | CSS @media print rules included |
| TOC generation | Optional table of contents via --toc |
| Frontmatter | Extracted for title, stripped from output |
Usage
# Basic conversion (professional style)
node .github/muscles/md-to-html.cjs report.md
# Academic style with TOC
node .github/muscles/md-to-html.cjs thesis.md --style academic --toc
# Dark mode output
node .github/muscles/md-to-html.cjs docs.md --style dark
# Mermaid diagrams rendered as PNG (high quality)
node .github/muscles/md-to-html.cjs architecture.md --mermaid-png
# Custom output path
node .github/muscles/md-to-html.cjs README.md output/readme.html
# Dry run (validate without generating)
node .github/muscles/md-to-html.cjs report.md --dry-run
# Debug mode (save preprocessed markdown)
node .github/muscles/md-to-html.cjs report.md --debug
Options Reference
| Option | Default | Description |
|---|---|---|
--style PRESET |
professional | Style preset: professional, academic, minimal, dark |
--toc |
off | Generate table of contents from headings |
--embed-images |
true | Convert local images to base64 data URIs |
--no-embed-images |
- | Keep image paths as-is (external references) |
--strip-frontmatter |
true | Remove YAML frontmatter from output |
--mermaid-png |
off | Render Mermaid as PNG (requires mmdc) |
--mermaid-fallback |
default | Convert Mermaid to table representation |
--debug |
off | Save preprocessed markdown as _debug_combined.md |
--dry-run |
off | Validate only, no HTML output |
Style Presets
| Preset | Font | Max Width | Colors | Best For |
|---|---|---|---|---|
| professional | Segoe UI | 900px | Blue headings, white bg | Business docs, reports |
| academic | Palatino Linotype | 750px | Dark headings, cream bg | Papers, theses |
| minimal | Inter | 800px | Black/gray, white bg | Clean, modern pages |
| dark | Segoe UI | 900px | Light text, dark bg | Dark mode preference |
Mermaid Diagram Support
| Diagram Type | PNG Mode | Fallback Mode |
|---|---|---|
| Flowchart | ✅ Full render | ✅ Table |
| Sequence | ✅ Full render | ✅ Table |
| Class | ✅ Full render | ✅ Table |
| State | ✅ Full render | ✅ Table |
| ER | ✅ Full render | ✅ Table |
| Gantt | ✅ Full render | ⚠️ Limited |
| Pie | ✅ Full render | ✅ Table |
| Journey | ✅ Full render | ⚠️ Limited |
PNG Mode (--mermaid-png): Requires mermaid-cli (mmdc). Renders at scale 8, 2400px width for crisp output. Diagrams are embedded as base64 PNGs.
Fallback Mode (default): No external dependencies. Converts diagram syntax to an ASCII table representation suitable for text-only viewing.
Print Styling
HTML output includes @media print CSS rules:
- Page breaks before H1 headings
- No background colors (ink-friendly)
- Link URLs shown after text
- Code blocks with borders instead of background
- Proper margins for binding
Batch Processing
# Convert all markdown files in a directory
for file in docs/*.md; do
node .github/muscles/md-to-html.cjs "$file" --style professional
done
# PowerShell equivalent
Get-ChildItem docs/*.md | ForEach-Object {
node .github/muscles/md-to-html.cjs $_.FullName --style professional
}
Troubleshooting
| Problem | Cause | Solution |
|---|---|---|
| "pandoc not found" | pandoc not installed | winget install pandoc |
| Mermaid not rendering | mmdc not installed | npm install -g @mermaid-js/mermaid-cli or use fallback |
| Images missing | Relative paths broken | Use --embed-images (default) |
| Output too wide on print | Style preset issue | Use academic style for print |
| Special characters garbled | Encoding issue | Ensure source is UTF-8 |
Requirements
- Node.js 18+
- pandoc (
winget install pandoc) - mermaid-cli (optional, only for
--mermaid-png)
Muscle Script
.github/muscles/md-to-html.cjs (v1.0.0)
Related Skills
- md-to-word — Sister converter for Word document output
- md-to-eml — Sister converter for email distribution
- md-scaffold — Generate converter-ready Markdown templates
- markdown-mermaid — Diagram authoring for embedded Mermaid
- lint-clean-markdown — Pre-validate markdown before conversion
- nav-inject — Add navigation tables for multi-file suites
Skill version: 2.0.0 | Last updated: 2026-04-14 | Category: document-conversion