Server

\documentclass[border=4pt]{standalone}

% --- packages (mirror these in server.meta.json "requires") ---
\usepackage{tikz}

% --- palette --------------------------------------------------------------
% Canonical definitions live in reference/color-palettes/; duplicated here so the
% file compiles standalone. Values are the color-blind-friendly Okabe-Ito set.
\definecolor{otblue}{HTML}{0072B2}
\definecolor{otorange}{HTML}{E69F00}
\definecolor{otteal}{HTML}{009E73}
\definecolor{otpurple}{HTML}{CC79A7}
\definecolor{otgray}{HTML}{5A5A5A}

\begin{document}
% ==== parameters (edit these) ============================================
\def\numunits{3}      % number of stacked rack units
\def\unitwidth{2.4}   % unit width  (cm)
\def\unitheight{0.7}  % unit height (cm)
\def\unitgap{0.18}    % vertical gap between units (cm)
% =========================================================================

\begin{tikzpicture}[
    server unit/.style={
      draw=otblue!75!black,
      line width=0.6pt,
      fill=otblue!12,
      rounded corners=1.2pt,
      minimum width=\unitwidth cm,
      minimum height=\unitheight cm,
    },
    led/.style={
      circle, fill=otteal, inner sep=0pt, minimum size=0.14cm,
    },
    vent/.style={draw=otblue!55!black, line width=0.7pt},
  ]

  % Stack the rack units bottom-to-top with stable names unit1..unitN.
  \foreach \i in {1,...,\numunits} {
    \pgfmathsetmacro{\ypos}{(\i-1)*(\unitheight+\unitgap)}
    \node[server unit, anchor=south west] (unit\i) at (0,\ypos) {};
    % status LED near the left edge
    \node[led] (led\i) at ([xshift=0.30cm]unit\i.west) {};
    % three ventilation slits near the right edge
    \foreach \j in {0,1,2} {
      \pgfmathsetmacro{\vx}{-0.35-\j*0.18}
      \draw[vent] ([xshift=\vx cm, yshift=-0.16cm]unit\i.east) -- ++(0,0.32cm);
    }
  }

\end{tikzpicture}
\end{document}