1. Introduction

This article explains Folio's LaTeX syntax for users already familiar with LaTeX. The main differences from standard LaTeX are as follows:

• No preamble needed — You don't need \documentclass, \usepackage, or \begin{document}

• KaTeX-based — Math rendering uses KaTeX

• Built-in theorem environments — 18+ environments like theorem, definition are ready to use

• Built-in code and diagram environments — lstlisting, mermaid, tikzgraph, tikzcd, etc. work out of the box

• Macros and references managed in Settings — \newcommand etc. are registered in the Settings preamble editor, and references are managed in the dashboard, applying to all articles

2. Section Structure

Folio supports six levels of headings. Numbers are assigned automatically.

\section{Section}
\subsection{Subsection}
\subsubsection{Subsubsection}
\paragraph{Paragraph}
\subparagraph{Subparagraph}

To suppress numbering, use the starred variant (\section*{...}).

3. Text Formatting

3.1. Font Styles

The main text formatting commands are summarized below:

3.2. Lists

Bullet lists (itemize):

\begin{itemize}
\item Item 1
\item Item 2
\end{itemize}

Result:

• Item 1

• Item 2

Numbered lists (enumerate):

\begin{enumerate}
\item First item
\item Second item
\item Third item
\end{enumerate}

Result:

1. First item

2. Second item

3. Third item

Description lists (description):

\begin{description}
\item[KaTeX] A fast math rendering library
\item[mermaid] A text-based diagramming syntax
\end{description}

Result:

KaTeX

A fast math rendering library

mermaid

A text-based diagramming syntax

tikzcd

A LaTeX package for commutative diagrams

4. Special Characters and Escaping

Characters with special meaning in LaTeX must be escaped with a backslash:

4.1. Dashes and Quotation Marks

5. Inline Code and Verbatim

Use \verb to embed short code or command names inline:

\verb|inline code|
\verb+alternative delimiters work too+

Delimiters can be any character, such as |, +, or !.

In a verbatim environment,
everything is displayed as-is.
\textbf{This won't be bold}
$x^2$ ← not rendered as math either

6. Differences from Standard LaTeX

A summary of the compatibility with standard LaTeX:

7. Summary

On Folio, you can start writing directly from \section without a preamble. Most basic LaTeX syntax for text formatting, lists, and special characters works as expected. In the next article, we'll take a detailed look at writing math.