\documentclass[a4paper]{article}
\usepackage[margin=0pt]{geometry}
\usepackage{tikz}
\usetikzlibrary{calc}
\pagestyle{empty}

\begin{document}
\begin{tikzpicture}[remember picture, overlay]

  % --- Layer 1: Gradient background ---
  \fill[top color={rgb,255:red,45;green,41;blue,38},
        bottom color={rgb,255:red,30;green,28;blue,26}]
    (current page.north west) rectangle (current page.south east);

  % --- Layer 2: Subtle angular / triangular shapes ---
  % Top-right cluster
  \fill[fill={rgb,255:red,58;green,54;blue,51}, opacity=0.35]
    (current page.north east)
    -- +(-90mm, 0)
    -- +(-30mm, -80mm)
    -- cycle;

  \fill[fill={rgb,255:red,58;green,54;blue,51}, opacity=0.20]
    ([xshift=-40mm] current page.north east)
    -- +(-70mm, 0)
    -- +(-20mm, -55mm)
    -- cycle;

  \fill[fill={rgb,255:red,58;green,54;blue,51}, opacity=0.15]
    ([xshift=-20mm, yshift=-30mm] current page.north east)
    -- +(-50mm, -10mm)
    -- +(-10mm, -60mm)
    -- cycle;

  % Bottom-left cluster
  \fill[fill={rgb,255:red,58;green,54;blue,51}, opacity=0.30]
    (current page.south west)
    -- +(80mm, 0)
    -- +(25mm, 70mm)
    -- cycle;

  \fill[fill={rgb,255:red,58;green,54;blue,51}, opacity=0.18]
    ([xshift=30mm] current page.south west)
    -- +(65mm, 0)
    -- +(15mm, 50mm)
    -- cycle;

  % Mid-edge shards
  \fill[fill={rgb,255:red,58;green,54;blue,51}, opacity=0.12]
    ([yshift=-120mm] current page.north west)
    -- +(40mm, -15mm)
    -- +(10mm, -45mm)
    -- cycle;

  \fill[fill={rgb,255:red,58;green,54;blue,51}, opacity=0.10]
    ([yshift=-80mm] current page.north east)
    -- +(-35mm, -20mm)
    -- +(-8mm, -50mm)
    -- cycle;

  % --- Layer 3: Gold accent elements ---

  % Main horizontal accent bar (2.5mm thick, full width, ~20mm from top)
  \fill[fill={rgb,255:red,212;green,165;blue,116}]
    ([yshift=-20mm] current page.north west)
    rectangle ([yshift=-22.5mm] current page.north east);

  % Left vertical stripe (thin, partial height)
  \fill[fill={rgb,255:red,212;green,165;blue,116}, opacity=0.6]
    ([xshift=12mm, yshift=-22.5mm] current page.north west)
    rectangle ([xshift=13.5mm, yshift=-140mm] current page.north west);

  % Diamond accent near left stripe
  \fill[fill={rgb,255:red,212;green,165;blue,116}, opacity=0.45]
    ([xshift=12.75mm, yshift=-145mm] current page.north west)
    -- +( 4mm, -6mm)
    -- +(0, -12mm)
    -- +(-4mm, -6mm)
    -- cycle;

  % Bottom-right triangle accent
  \fill[fill={rgb,255:red,184;green,134;blue,11}, opacity=0.25]
    (current page.south east)
    -- +(-60mm, 0)
    -- +(0, 45mm)
    -- cycle;

  % Secondary triangle above main bar
  \fill[fill={rgb,255:red,184;green,134;blue,11}, opacity=0.18]
    ([xshift=-100mm, yshift=-14mm] current page.north east)
    -- +(35mm, 0)
    -- +(18mm, -6mm)
    -- cycle;

\end{tikzpicture}
\end{document}
