\ref gets section number instead of theorem number using tcolorbox

Question

I found a nice template for my notes but I'm having trouble getting it to reference definitions and theorems correctly, as \ref displays the section number instead of the definition number.

\documentclass{report}
\usepackage{xcolor}
\usepackage[most]{tcolorbox}
\definecolor{primary}{RGB}{60, 0, 163}
\NewDocumentCommand\caja{m O{\Large #1} O{grisfondo} O{primary} O{number within=section}}
{
    \newtcbtheorem[#5]{#1}{\large #2}
    {%
        enhanced
        ,breakable
        ,colback = #3
        ,frame hidden
        ,boxrule = 0sp
        ,borderline west = {2pt}{0pt}{#4}
        ,sharp corners
        ,detach title
        ,before upper = \tcbtitle\par\smallskip
        ,coltitle = #4
        ,fonttitle = \bfseries\sffamily
        ,separator sign none
        ,segmentation style={solid, #4}
    }
    {th}
}
\caja{defi}[Definición][primary!12][primary]
\newcommand{\dfe}[2]{\begin{defi}{#1}{}#2\end{defi}}
\begin{document}
\chapter{}
\section{Section}
\section{The thing that appears in the reference}
\dfe{What I want to appear in the reference}{
This is a definition
\label{def:firstdef}
}
A reference \ref{def:firstdef} whose expected outcome is 1.2.1.
\end{document}