% Loading packages in the preamble
\documentclass{article}

% Essential packages
\usepackage[utf8]{inputenc}    % Input encoding
\usepackage[T1]{fontenc}       % Font encoding
\usepackage[english]{babel}    % Language support
\usepackage{graphicx}          % Graphics inclusion
\usepackage{amsmath}           % Enhanced mathematics

% Packages with options
\usepackage[margin=1in]{geometry}     % Page layout
\usepackage[style=authoryear]{biblatex}  % Bibliography
\usepackage[table,xcdraw]{xcolor}     % Colors

\begin{document}
% Package commands now available
\includegraphics{image.png}    % From graphicx
\textcolor{blue}{Blue text}    % From xcolor
\begin{align}                  % From amsmath
  E &= mc^2
\end{align}
\end{document}

% CTAN is the central repository for LaTeX packages
% Visit: https://ctan.org

% Common search strategies:
% 1. Browse by topic: https://ctan.org/topics
% 2. Search by name: https://ctan.org/search
% 3. Browse alphabetically: https://ctan.org/pkg

% Popular package categories:
% - Graphics: tikz, pgfplots, graphicx
% - Mathematics: amsmath, mathtools, physics
% - Tables: booktabs, array, longtable
% - Bibliography: biblatex, natbib
% - Code: listings, minted, algorithm2e
% - Fonts: fontspec, lmodern, libertine

# Command line (if you have LaTeX installed locally)
texdoc packagename          # Opens package documentation
texdoc graphicx            # Example: graphicx documentation
texdoc amsmath             # Example: amsmath documentation

# Alternative methods:
# 1. CTAN package page: https://ctan.org/pkg/packagename
# 2. Google: "latex packagename documentation"
# 3. LaTeX package galleries and guides

% Essential mathematics
\usepackage{amsmath}      % Enhanced math environments
\usepackage{amssymb}      % Additional math symbols
\usepackage{mathtools}    % Extensions to amsmath

% Graphics and figures
\usepackage{graphicx}     % Include graphics
\usepackage{tikz}         % Create graphics programmatically
\usepackage{pgfplots}     % Create plots and charts

% Tables and arrays
\usepackage{booktabs}     % Professional table formatting
\usepackage{array}        % Enhanced column types
\usepackage{longtable}    % Multi-page tables

% Text formatting
\usepackage{microtype}    % Improved typography
\usepackage{enumitem}     % Customizable lists
\usepackage{fancyhdr}     % Custom headers/footers

% Colors and styling
\usepackage{xcolor}       % Color support
\usepackage{listings}     % Code listings
\usepackage{hyperref}     % Hyperlinks and PDF features

% Bibliography and citations
\usepackage{biblatex}     % Modern bibliography (recommended)
\usepackage{natbib}       % Traditional bibliography

% These packages work immediately in LaTeX Cloud Studio:
\usepackage{amsmath}      ✓ Mathematics
\usepackage{graphicx}     ✓ Graphics
\usepackage{tikz}         ✓ Drawings
\usepackage{booktabs}     ✓ Tables
\usepackage{listings}     ✓ Code
\usepackage{biblatex}     ✓ Bibliography
\usepackage{hyperref}     ✓ Links
\usepackage{xcolor}       ✓ Colors
\usepackage{geometry}     ✓ Page layout
\usepackage{fancyhdr}     ✓ Headers/footers
% And hundreds more...

# TeX Live (Linux/macOS/Windows)
sudo apt-get install texlive-full    # Ubuntu/Debian
brew install --cask mactex           # macOS
# Windows: Download from https://tug.org/texlive/

# MiKTeX (Windows/macOS/Linux)
# Download from https://miktex.org/
# Automatically installs packages on first use

# Manual package installation (if needed)
# 1. Download package from CTAN
# 2. Extract to appropriate directory
# 3. Run texhash to update database
# 4. Update package database if required

\documentclass{article}

% 1. Input/Output encoding (first)
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}

% 2. Language and fonts
\usepackage[english]{babel}
\usepackage{lmodern}

% 3. Page layout
\usepackage[margin=1in]{geometry}

% 4. Mathematics (early for widespread use)
\usepackage{amsmath,amssymb}

% 5. Graphics and colors
\usepackage{graphicx}
\usepackage{xcolor}

% 6. Tables and lists
\usepackage{booktabs}
\usepackage{enumitem}

% 7. Bibliography (before hyperref)
\usepackage[backend=biber]{biblatex}

% 8. Hyperref (near the end)
\usepackage{hyperref}

% 9. Packages that must load after hyperref
\usepackage{cleveref}

\begin{document}
% Content here
\end{document}

% Packages often accept options to modify behavior

% Geometry with specific margins
\usepackage[
  top=1in,
  bottom=1in,
  left=1.5in,
  right=1in,
  headheight=15pt
]{geometry}

% Babel with multiple languages
\usepackage[english,spanish,french]{babel}

% Biblatex with style and backend
\usepackage[
  backend=biber,
  style=authoryear,
  sorting=nyt,
  maxcitenames=2
]{biblatex}

% Hyperref with link colors
\usepackage[
  colorlinks=true,
  linkcolor=blue,
  citecolor=green,
  urlcolor=red
]{hyperref}

% Listings with default language
\usepackage[language=Python]{listings}

% Multiple options for xcolor
\usepackage[table,xcdraw,dvipsnames]{xcolor}

% Check if package is available
\IfPackageExists{microtype}{
  \usepackage{microtype}
  \newcommand{\hasmicrotype}{true}
}{
  \newcommand{\hasmicrotype}{false}
}

% Load different packages based on compiler
\usepackage{iftex}
\ifPDFTeX
  \usepackage[utf8]{inputenc}
  \usepackage[T1]{fontenc}
\else
  \usepackage{fontspec}
\fi

% Version-specific loading
\@ifpackagelater{tikz}{2020/12/27}{
  % TikZ version 3.1.8 or later
  \usetikzlibrary{new-features}
}{
  % Older TikZ version
  \usetikzlibrary{legacy-features}
}

% Global options vs package options
\documentclass[12pt]{article}  % Global option affects all packages
\usepackage{geometry}          % Inherits 12pt if relevant

% Override global options
\usepackage[10pt]{package}     % This package uses 10pt regardless

% Conflict: subfigure vs subcaption
% DON'T DO THIS:
% \usepackage{subfigure}    % Obsolete
% \usepackage{subcaption}   % Modern
% DO THIS:
\usepackage{subcaption}     % Use only the modern package

% Conflict: times vs newtx
% DON'T DO THIS:
% \usepackage{times}        % Obsolete
% \usepackage{newtxtext}    % Modern replacement
% DO THIS:
\usepackage{newtxtext,newtxmath}  % Complete modern replacement

% Conflict: hyperref positioning
% WRONG ORDER:
% \usepackage{cleveref}
% \usepackage{hyperref}
% CORRECT ORDER:
\usepackage{hyperref}
\usepackage{cleveref}

% Resolving font encoding conflicts
\usepackage{iftex}
\ifPDFTeX
  \usepackage[utf8]{inputenc}  % For pdflatex
  \usepackage[T1]{fontenc}
\else
  \usepackage{fontspec}        % For xelatex/lualatex
\fi

% Method 1: Minimal example
\documentclass{article}
\usepackage{problematic-package}
\begin{document}
Test content
\end{document}

% Method 2: Load packages incrementally
\documentclass{article}
% \usepackage{package1}     % Comment out packages one by one
% \usepackage{package2}     % to identify conflicts
% \usepackage{package3}
\usepackage{package4}       % Until you find the problematic combination

% Method 3: Check package versions
\listfiles                  % Add this before \begin{document}
% This will list all loaded packages and versions in the log

% Method 4: Verbose error reporting
\errorcontextlines=999      % Show more context in error messages
\tracingmacros=1           % Trace macro expansions (very verbose!)

% Core mathematics
\usepackage{amsmath}        % Essential math environments
\usepackage{amssymb}        % Additional symbols
\usepackage{mathtools}      % Enhanced amsmath

% Advanced mathematics
\usepackage{physics}        % Physics notation
\usepackage{siunitx}        % SI units
\usepackage{tensor}         % Tensor notation
\usepackage{cancel}         % Cancel terms in equations

% Chemistry
\usepackage{mhchem}         % Chemical formulas
\usepackage{chemfig}        % Chemical structures
\usepackage{chemmacros}     % Chemical macros

% Algorithm typesetting
\usepackage{algorithm}      % Algorithm floats
\usepackage{algpseudocode}  % Pseudocode
\usepackage{algorithm2e}    % Alternative algorithm package

% Basic graphics
\usepackage{graphicx}       % Include images
\usepackage{rotating}       % Rotate content
\usepackage{wrapfig}        % Wrap text around figures

% Advanced graphics
\usepackage{tikz}           % Programmatic graphics
\usepackage{pgfplots}       % Data plotting
\usepackage{circuitikz}     % Circuit diagrams

% Subfigures
\usepackage{subcaption}     % Modern subfigures
\usepackage{subfig}         % Alternative (less recommended)

% Figure positioning
\usepackage{float}          % Enhanced float control
\usepackage{placeins}       % Float barriers

% Typography
\usepackage{microtype}      % Improved typography
\usepackage{setspace}       % Line spacing control
\usepackage{parskip}        % Paragraph spacing

% Page layout
\usepackage{geometry}       % Page dimensions
\usepackage{fancyhdr}       % Headers and footers
\usepackage{titlesec}       % Section title formatting

% Lists and itemization
\usepackage{enumitem}       % Customizable lists
\usepackage{mdwlist}        % Compact lists

% Tables
\usepackage{booktabs}       % Professional tables
\usepackage{array}          % Enhanced column types
\usepackage{tabularx}       % Auto-width tables
\usepackage{longtable}      % Multi-page tables
\usepackage{ltxtable}       % Combination of longtable and tabularx

% Code listings
\usepackage{listings}       % Basic code listings
\usepackage{minted}         % Advanced syntax highlighting (requires pygments)
\usepackage{fancyvrb}       % Enhanced verbatim

% Listings configuration
\lstset{
  language=Python,
  basicstyle=\ttfamily\small,
  keywordstyle=\color{blue},
  commentstyle=\color{green},
  stringstyle=\color{red},
  numbers=left,
  numberstyle=\tiny,
  breaklines=true
}

% Minted configuration
\setminted{
  fontsize=\small,
  linenos=true,
  breaklines=true,
  frame=lines
}

% mypackage.sty - Custom package file
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{mypackage}[2024/01/01 My Custom Package]

% Package options
\newif\if@myoption
\@myoptionfalse
\DeclareOption{myoption}{\@myoptiontrue}
\ProcessOptions\relax

% Required packages
\RequirePackage{amsmath}
\RequirePackage{xcolor}

% Custom commands
\newcommand{\highlight}[1]{\textcolor{yellow}{#1}}
\newcommand{\important}[1]{\textbf{\textcolor{red}{#1}}}

% Custom environments
\newenvironment{myenv}{%
  \begin{center}\color{blue}\bfseries
}{%
  \end{center}
}

% Conditional code based on options
\if@myoption
  \newcommand{\optionalcommand}{This appears with myoption}
\else
  \newcommand{\optionalcommand}{This appears without myoption}
\fi

% Require specific package version
\usepackage{l3packages}
\ExplSyntaxOn
\msg_new:nnn { mypackage } { version-too-old }
  { Package~'#1'~is~too~old.~Required:~#2,~Found:~#3 }

% Check if package version is sufficient
\@ifpackagelater{tikz}{2020/12/27}{
  % Version is 3.1.8 or later
}{
  \msg_error:nnn { mypackage } { version-too-old } { tikz } { 3.1.8 } { \@ifpackageloaded{tikz}{\csname [email protected]\endcsname}{not loaded} }
}
\ExplSyntaxOff

% Alternative simple version check
\@ifpackagelater{amsmath}{2017/09/02}{}{
  \PackageError{mydocument}{amsmath package too old}{}
}

% Document header with package requirements
%
% Required packages:
% - amsmath (core LaTeX distribution)
% - graphicx (core LaTeX distribution)
% - tikz (CTAN: tikz)
% - booktabs (CTAN: booktabs)
% - biblatex with biber backend
%
% Optional packages:
% - microtype (improved typography)
% - hyperref (PDF links and bookmarks)
%
% Compilation: pdflatex -> biber -> pdflatex -> pdflatex
%

\documentclass{article}

% Package loading with version comments
\usepackage{amsmath}        % v2.17 or later
\usepackage{graphicx}       % v1.1 or later
\usepackage{tikz}           % v3.1.8 or later for advanced features
\usepackage{booktabs}       % v1.6 or later
\usepackage[backend=biber]{biblatex}  % v3.16 or later

% Document content
\begin{document}
Content requiring the above packages...
\end{document}

% Error: Package not found
% Solution: Check package name spelling
\usepackage{graphicx}  % Correct
% \usepackage{graphics}  % Common misspelling

% Error: Option clash
% Problem:
% \usepackage[utf8]{inputenc}
% \usepackage[latin1]{inputenc}  % Conflict!
% Solution: Use global options or load once
\PassOptionsToPackage{utf8}{inputenc}
\usepackage{inputenc}

% Error: Command redefinition
% Problem: Two packages define \example
% Solution: Rename one command
\usepackage{package1}
\let\exampleoriginal\example
\usepackage{package2}  % Redefines \example
\let\examplenew\example
\let\example\exampleoriginal  % Restore original

% Error: Unknown option
% Check package documentation for valid options
\usepackage[colorlinks=true]{hyperref}  % Valid option
% \usepackage[invalidoption]{hyperref}   % Would cause error