% ============================================================
%  digiradio-manual.sty — visual style for the DigiRadio manual
%  Optima-like humanist sans, 12pt, 1.3 leading, restrained colour,
%  and clear at-a-glance tcolorbox callouts.
%
%  Use with a 12pt KOMA class, e.g.:
%     \documentclass[12pt,a4paper]{scrartcl}
%     \usepackage{digiradio-manual}
%
%  FONT: compile with LuaLaTeX or XeLaTeX to get the real Optima
%  (a system font on macOS). With pdfLaTeX it falls back to Linux
%  Biolinum, a humanist sans in the same spirit. The package detects
%  the engine automatically.
% ============================================================
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{digiradio-manual}[2026/07/06 DigiRadio manual style]

\RequirePackage[table,dvipsnames]{xcolor}
\RequirePackage{iftex}
\RequirePackage{geometry}
\RequirePackage{microtype}
\RequirePackage{setspace}
\RequirePackage{titlesec}
\RequirePackage{booktabs}
\RequirePackage{array}
\RequirePackage{enumitem}
\RequirePackage[most]{tcolorbox}
\RequirePackage{graphicx}

% ---------- Fonts (engine-aware) ---------------------------------------
\ifPDFTeX
  \RequirePackage[T1]{fontenc}
  \RequirePackage[utf8]{inputenc}
  \RequirePackage{libertine}            % Linux Libertine + Biolinum
  \renewcommand{\familydefault}{\sfdefault} % Biolinum as body (Optima-like)
\else
  \RequirePackage{fontspec}
  % Real Optima on macOS; change the name if yours differs.
  \IfFontExistsTF{Optima}{%
    \setmainfont{Optima}%
  }{%
    \setmainfont{Linux Biolinum O}% fallback if Optima not installed
  }
\fi

% ---------- Colour palette (elegant, restrained) -----------------------
% Two signature colours (petrol + amber), a muted red reserved for
% cautions, plus ink and neutral. Backgrounds are light tints of these.
\definecolor{drPetrol}{HTML}{0F4C5C}   % primary — headings, notes
\definecolor{drAmber} {HTML}{C46210}   % accent  — key ideas, emphasis
\definecolor{drTeal}  {HTML}{1A7F72}   % secondary — references
\definecolor{drRed}   {HTML}{A4303F}   % caution only
\definecolor{drInk}   {HTML}{1B1B1D}   % body text
\definecolor{drGray}  {HTML}{5A5F63}   % captions, rules

\color{drInk}

% ---------- Page geometry & spacing ------------------------------------
\geometry{a4paper, top=2.6cm, bottom=2.6cm, inner=2.6cm, outer=3.2cm,
          marginparwidth=2.4cm}
\setstretch{1.3}
\setlength{\parskip}{0.5\baselineskip}
\setlength{\parindent}{0pt}

% ---------- Links -------------------------------------------------------
\RequirePackage{hyperref}
\hypersetup{colorlinks=true, linkcolor=drPetrol, urlcolor=drAmber,
            citecolor=drTeal}

% ---------- Chapter heading (for report-class manuals) -----------------
\titleformat{\chapter}[display]
  {\color{drPetrol}\bfseries}
  {\filright\color{drAmber}\large\MakeUppercase{\chaptertitlename}\ \thechapter}
  {6pt}{\Huge}
  [\vspace{3pt}{\color{drAmber}\titlerule[1.5pt]}]
\titlespacing*{\chapter}{0pt}{0pt}{22pt}

% ---------- Section headings (coloured, sans, distinctive) -------------
\titleformat{\section}
  {\color{drPetrol}\Large\bfseries}
  {\color{drAmber}\thesection\quad}{0pt}{}
  [{\color{drAmber}\titlerule[1.2pt]}]
\titleformat{\subsection}
  {\color{drPetrol}\large\bfseries}
  {\color{drAmber}\thesubsection\quad}{0pt}{}
\titleformat{\subsubsection}
  {\color{drPetrol}\normalsize\bfseries}
  {\thesubsubsection\quad}{0pt}{}
\titleformat{\paragraph}[runin]
  {\bfseries\color{drPetrol}}{}{0pt}{}[\;]
\titlespacing*{\paragraph}{0pt}{0.6\baselineskip}{0.8em}
\titlespacing*{\section}{0pt}{1.4\baselineskip}{0.5\baselineskip}

% ---------- List markers (coloured) ------------------------------------
\setlist[itemize,1]{label=\textcolor{drAmber}{\textbullet}, leftmargin=*}
\setlist[itemize,2]{label=\textcolor{drTeal}{\textendash}}
\setlist[enumerate,1]{label=\textcolor{drAmber}{\bfseries\arabic*.},
                      leftmargin=*}

% ---------- Callout boxes (clear at a glance) --------------------------
\tcbuselibrary{skins,breakable}

% Shared base: rounded, light tinted body, bold coloured title bar
% clipped to the top-left, and an accent rule down the left edge.
\tcbset{dr@base/.style={
  enhanced, breakable, boxrule=0pt, frame hidden, sharp corners=downhill,
  arc=1.4mm, left=3.5mm, right=3.5mm, top=3mm, bottom=3mm,
  fonttitle=\bfseries\small, coltitle=white,
  attach boxed title to top left={xshift=3mm, yshift=-2.4mm},
  boxed title style={boxrule=0pt, arc=0.8mm,
                     left=2.2mm, right=2.2mm, top=0.6mm, bottom=0.6mm},
  before skip=8pt, after skip=8pt,
}}

\newtcolorbox{drnote}[1][Note]{dr@base,
  colback=drPetrol!6, colbacktitle=drPetrol,
  borderline west={2.6pt}{0pt}{drPetrol}, title={#1}}

\newtcolorbox{drkey}[1][Key idea]{dr@base,
  colback=drAmber!9, colbacktitle=drAmber,
  borderline west={2.6pt}{0pt}{drAmber}, title={#1}}

\newtcolorbox{drcaution}[1][Caution]{dr@base,
  colback=drRed!7, colbacktitle=drRed,
  borderline west={2.6pt}{0pt}{drRed}, title={#1}}

\newtcolorbox{drref}[1][Datasheet]{dr@base,
  colback=drTeal!7, colbacktitle=drTeal,
  borderline west={2.6pt}{0pt}{drTeal}, title={#1}}

\newtcolorbox{drdecision}[1][Design decision]{dr@base,
  colback=drPetrol!5, colbacktitle=drGray,
  borderline west={2.6pt}{0pt}{drGray}, title={#1}}

% ---------- Table helpers ----------------------------------------------
% A coloured header row for booktabs tables. Usage:
%   \begin{tabular}{...}
%     \drhead Col A & Col B \\   % coloured header row
%     \midrule ...
\newcommand{\drhead}{\rowcolor{drPetrol}\color{white}\bfseries}
% Subtle zebra striping if wanted: \rowcolors{2}{drPetrol!5}{white}
% ---------- Code listings (styled to match the callouts) ---------------
\tcbuselibrary{listings}
\lstdefinestyle{drcpp}{%
  language=C++,
  basicstyle=\ttfamily\small,
  keywordstyle=\color{drPetrol}\bfseries,
  commentstyle=\color{drGray}\itshape,
  stringstyle=\color{drTeal},
  numberstyle=\color{drGray}\scriptsize,
  numbers=left, numbersep=9pt,
  showstringspaces=false,
  tabsize=2, breaklines=true, keepspaces=true,
  morekeywords={constexpr,noexcept,nullptr,override,final,explicit,
                enum,class,namespace,using,co_await,std,expected,span,
                uint32_t,uint8_t},
}
% drcode: a code block with the same title bar + left accent as the boxes
\newtcblisting{drcode}[1][Listing]{%
  dr@base,
  colback=drPetrol!4, colbacktitle=drGray,
  borderline west={2.6pt}{0pt}{drGray},
  title={#1},
  listing only, listing style=drcpp,
}
% inline code: \drcode|std::expected<T,E>|
\newcommand{\code}[1]{{\ttfamily\color{drPetrol}#1}}

\endinput