Sean

The Grand Markdown Syntax Showcase

Edited

This document aims to demonstrate a wide array of Markdown features. It includes everything from basic formatting to advanced elements, deliberately constructed with complexity to thoroughly test your CSS rendering capabilities, now including mathematical typesetting via KaTeX.

Document Goals:

  1. Test text formatting (bold, italics, strikethrough, combinations).
  2. Test nested lists (ordered, unordered, task lists).
  3. Test inline code and code blocks (with syntax highlighting).
  4. Test links and images.
  5. Test > blockquotes (nested).
  6. Test tables (alignment, complex content).
  7. Test KaTeX math rendering ($...$ and $$...$$).
  8. Test miscellaneous elements (horizontal rules, footnotes, HTML).

Placehold Service Demonstration

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A simple, fast, and free image placeholder service. We’ll use it extensively below.

Main Placeholder Banner

Documentation Snippets

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How does it work exactly?

Size (H3 Heading)

Specify size using width x height:

https://placehold.co/350x100 -> 350x100 Placeholder

Height is optional for squares:

https://placehold.co/120 -> 120x120 Square

Max size 4000x4000px, Min size 10x10px.

Format (H4 Heading)

Specify image format:

  • SVG (default): SVG Format
  • PNG: PNG Format
  • JPEG: JPEG Format
  • WebP: WebP Format

Combine format with colors: https://placehold.co/220x50/000/FFF.png -> Colored PNG

Color (H5 Heading)

Use hex values for background/text:

https://placehold.co/200x50/FFA500/FFF -> Hex Colors

Or CSS color names:

https://placehold.co/200x50/lightblue/darkblue -> CSS Name Colors

transparent keyword is also valid:

https://placehold.co/200x50/transparent/F00 -> Transparent BG

Text & Font (H6 Heading)

Customize text via query string. Spaces use +, newlines use \\n.

https://placehold.co/320x70?text=Line+One\\nLine+Two+with+Spaces -> Custom Text

Use font parameter (e.g., roboto):

https://placehold.co/300x60?text=Roboto+Font+Example&font=roboto -> Roboto Font

Supported fonts (partial list):

Lato Font Sample Montserrat Font Sample Poppins Font Sample

Retina Support: Append @2x or @3x (PNG, JPEG, GIF, WebP, AVIF only):

https://placehold.co/[email protected] -> Retina @2x Example

List Testing (H2 Heading)

Unordered Lists

  • List item 1
    • Nested item 1.1
      • Deeper nesting 1.1.1
        • Deepest level? 1.1.1.1
          • Okay, one more: 1.1.1.1.1
    • Nested item 1.2 
      // Code block inside a list item
function greet(name) {
  console.log(`Hello, ${name}! Testing list code.`);
}
greet('Markdown User');
  • List item 2

    A blockquote within a list item. It can span multiple lines.

  • List item 3, containing italics, bold, and inline code.

Ordered Lists

  1. First item
    1. Sub-item A Ordered List Image
    2. Sub-item B
      1. Even deeper: B.1
      2. Even deeper: B.2
  2. Second item
    • Unordered sub-item I
    • Unordered sub-item II
      1. Ordered again 1
      2. Ordered again 2
  3. Third item

Task Lists

  • Completed task
    • Sub-task A (Done)
    • Sub-task B (Pending)
      • Nested pending task
  • Incomplete task
  • Another incomplete task

Blockquote Testing (H2 Heading)

This is a standard blockquote. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer nec odio. Praesent libero.

Nested blockquotes:

Level 2 quote.

Level 3 quote with bold and italic text.

Back to level 2.

Back to level 1. You can include other elements:

  • List Item 1 inside quote
  • List Item 2 inside quote
# Code block within a quote
class QuoteClass:
    def __init__(self, text):
        self.text = text
        print(f"Quoted: {self.text}")

Image within a quote: Quote Image

usgs-zqX9icQfc2I-unsplash-1.jpg

Code Block Testing (H2 Heading)

Here’s an example of inline code.

Fenced code blocks for different languages:

JavaScript:

import React, { useState } from 'react';
 
function Counter() {
  // JS code block comment
  const [count, setCount] = useState(0);
 
  return (
    <div className="counter-widget">
      <p>Count: {count}</p>
      <button onClick={() => setCount(count + 1)}>Increment</button>
      {/* Example Image */}
      <img src="https://placehold.co/180x40/a0a/fff?text=JS+Counter+Img" alt="JS Counter" />
    </div>
  );
}
 
export default Counter;

Python:

# -*- coding: utf-8 -*-
import requests
 
def fetch_data(url):
  """Fetches data from a URL. Includes a docstring."""
  try:
    response = requests.get(url, timeout=10)
    response.raise_for_status() # Raise HTTPError for bad responses (4xx or 5xx)
    # TODO: Add data processing logic
    return response.json()
  except requests.exceptions.RequestException as e:
    print(f"Error fetching data: {e}")
    return None
 
# Example usage
api_url = "https://api.example.com/data" 
# data = fetch_data(api_url) # Commented out for example

CSS:

/* CSS code block example */
body {
  font-family: 'Helvetica Neue', Arial, sans-serif; /* Set font stack */
  line-height: 1.7;
  color: #444; /* Default text color */
  background-color: #fafafa; /* Page background */
  margin: 1em;
}
 
h1, h2, h3, h4, h5, h6 {
  color: #222;
  margin-top: 1.5em;
  margin-bottom: 0.5em;
  border-bottom: 2px solid #eee; /* Header underline */
  padding-bottom: 0.3em;
}
 
code {
  background-color: #f0f0f0; /* Inline code background */
  padding: 0.2em 0.5em;
  border-radius: 4px;
  font-family: 'Courier New', monospace;
}
 
pre > code {
  background-color: #2d2d2d; /* Code block background (dark) */
  color: #ccc; /* Code block text color */
  display: block;
  padding: 1.5em;
  overflow-x: auto; /* Horizontal scroll */
  border-radius: 5px;
}

No Specific Language:

This is a plain code block without language specification.
Useful for raw text output or unsupported languages.
  Indentation is preserved.
Special characters like < > & should be displayed literally.

KaTeX Math Expression Testing (H2 Heading)

Markdown can be extended to support mathematical notation using KaTeX.

Inline math uses single dollar signs: E=mc2E=mc^2. This formula, ∑i=1ni=n(n+1)2\sum_{i=1}^{n} i = \frac{n(n+1)}{2}, should appear within the text flow. Greek letters like α,β,γ\alpha, \beta, \gamma are common.

Block math uses double dollar signs and is displayed on its own line:

∫abf(x)dx=F(b)−F(a)\int_a^b f(x) dx = F(b) - F(a)

Here’s a more complex example, the quadratic formula:

x=−b±b2−4ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}

Matrices are also possible:

A=(abcd),I=(1001)\mathbf{A} = \begin{pmatrix} a & b \\ c & d \end{pmatrix}, \quad \mathbf{I} = \begin{pmatrix} 1 & 0 \\ 0 & 1 \end{pmatrix}

And Maxwell’s equations in differential form:

∇⋅E=ρε0∇⋅B=0∇×E=−∂B∂t∇×B=μ0(J+ε0∂E∂t)\begin{aligned} \nabla \cdot \mathbf{E} &= \frac{\rho}{\varepsilon_0} \\ \nabla \cdot \mathbf{B} &= 0 \\ \nabla \times \mathbf{E} &= -\frac{\partial \mathbf{B}}{\partial t} \\ \nabla \times \mathbf{B} &= \mu_0 \left( \mathbf{J} + \varepsilon_0 \frac{\partial \mathbf{E}}{\partial t} \right) \end{aligned}

Testing fractions and limits:

L=lim⁡x→cf(x)and∂2u∂x2+∂2u∂y2=0L = \lim_{x \to c} f(x) \quad \text{and} \quad \frac{\partial^2 u}{\partial x^2} + \frac{\partial^2 u}{\partial y^2} = 0

Table Testing (H2 Heading)

Header 1 (Left Align)Header 2 (Center Align)Header 3 (Right Align)Header 4 (Mixed Content)
Cell 1-1Cell 1-2Cell 1-3Bold Text
Cell 2-1 CodeCell 2-2 ItalicsCell 2-3Link
Cell 3-1Table Img12345.67Strikethrough
A longer cell content to test wrapping and alignment behavior.code in cell‘a2+b2‘`\sqrt{a^2+b^2}`Mixed content bits
Math in table cellPQ\frac{P}{Q}Final cell 3-3End of row 4

Images

  • Inline Image: Small Icon
  • Reference Style Image: Reference Image
  • Linked Image: Linked Placeholder

Other Syntax Elements (H2 Heading)

Horizontal Rules

Created using three or more hyphens, asterisks, or underscores:

HTML Tags

Markdown often allows embedding raw HTML:

Press Ctrl + Shift + Esc to open Task Manager. Water is H2O. The famous equation is E=mc2. This text is highlighted.

Click to Expand (Details/Summary)

This is hidden content revealed upon clicking.

  • It can contain lists.
  • And other HTML elements.
  • ![Image in Details](https://placehold.co/120x40/eee/777?text=Details+Img)
  • Even math: $a^2 + b^2 = c^2$
This is a DIV element with inline CSS styling.

It acts as a container.

Nested blockquote inside HTML div.

Container

Escaping Characters

To display literal Markdown characters, use a backslash \ before them:

*Not italics* **Not bold** `Not code` # Not a heading [Not a link](http://example.com) ![Not an image](http://example.com/img.png) $Not math$ $\Not math block$

Footnotes

Here is some text requiring a footnote1. Here is another point needing elaboration2. And a third one for good measure3.

Conclusion (H2 Heading)

This document has demonstrated a substantial range of Markdown features: multiple heading levels, text styling, complex lists (nested, ordered, unordered, task), blockquotes (nested with content), code rendering (inline, fenced blocks with highlighting), tables (alignment, varied content including math), links (various types), images (using Placehold.co extensively, linked), KaTeX math expressions (inline and block), horizontal rules, embedded HTML, character escaping, and footnotes. It should serve as a robust test case for your CSS styling.

Footer Image

Footnotes

  1. This is the first footnote’s content. Short and simple. ↩

  2. This is the second, longer footnote. It can span multiple paragraphs if needed, although rendering might vary. It can also contain formatting like code or even italics.

    Blockquotes can potentially be included in footnotes depending on the Markdown processor’s capabilities. L=−14FμνFμν\mathcal{L} = -\frac{1}{4} F_{\mu\nu} F^{\mu\nu}

    ↩

  3. The third footnote, just to show multiple footnotes are handled. ↩