Syntax Highlighting
Syntax highlighting can be enabled in the Style preferences. It will recognize code blocks, detect the language and render color-coded output in the preview. There are multiple themes available, selected by the dropdown below the option in preferences. The selected theme will apply to all documents.
Marked uses highlight.js to provide consistent color coding for all types of embedded code, including standard Markdown syntaxes that don’t allow language to be specified. Highlight.js autodetects well. There are some minor rendering differences between it and colorizers such as Pygments (GitHub style), but the output is similar. Using the github.css theme on Ruby code, for example, renders almost the exact output you’d see on GitHub.
The GitHub stylesheet provides backup styles for blocks rendered with Pygments. If the <pre> tag is inside a div with the class “highlight”, it will display using the standard GitHub styling, not Marked’s. You can render the code externally and paste HTML, or use pygmentize to render it to html files and include them with the <<(source.html) syntax.
Syntax highlighting will show up in the preview and in print and PDF export. If enabled in preferences and the theme is included when exporting HTML, the highlight.js library used by Marked will be embedded in the HTML output, allowing your exported HTML to appear as it does in Marked.