\newcommand{\header}[3]{%

% HEADER flottant absolu (au-dessus de tout)
\begin{tikzpicture}[remember picture,overlay]
  \node[
    anchor=north,
    inner sep=0pt,
    outer sep=0pt
  ] at (current page.north) {%

    % ==== TON HEADER ORIGINAL (INCHANGÉ) ====
    \begin{tcolorbox}[
        colback=headercolor,
        colframe=headercolor,
        boxsep=0pt,
        sharp corners,
        left=3cm,
        right=3cm,
        top=0mm,
        bottom=0mm,
        width=\paperwidth
    ]
    \begin{tabular}{m{0.3\linewidth} m{0.35\linewidth} m{0.3\linewidth}}
        % Logo gauche
        \raggedright\includegraphics[height=8cm]{Logo/Logo_Defense_PNG.png} &

        % Titre centré
        \centering
        \begin{tcolorbox}[
            width=15cm,
            top=0mm,
            bottom=3cm,
            boxsep=0pt,
            center,
            colback=headercolor,
            colframe=headercolor,
            boxrule=0pt,
            sharp corners
        ]
            \begin{tcolorbox}[
                width=30cm,
                height=10mm,
                center,
                colback=goldColor,
                colframe=goldColor
            ]
            \end{tcolorbox}
            \vspace{1cm}
            \centering\fontsize{72pt}{84pt}\textcolor{mediumBlue}{\textbf{{#1}}}\\
            \vspace{3mm}
            \centering\fontsize{36pt}{48pt}\lora\textcolor{mediumBlue}{\textit{{#2}}}
        \end{tcolorbox}
        &

        % Logo droite ( To place if u want to include the logo of a partner organization.(remove the "%")
        %\raggedleft\includegraphics[height=8cm]{Logo/IRSD Logo.png}
    \end{tabular}
    \end{tcolorbox}
    % ==== FIN HEADER ORIGINAL ====

  };
\end{tikzpicture}

% Décalage du contenu pour passer en dessous du header
\vspace*{10cm}
\par
}