Nested boxes around a few items in an itemize environment

Question

this is kind of a follow up of this question, where someone asked how to create a box around a few items in an itemize environment. I'm facing a similar issue, but my case is a little bit more complex, as I want to be able to generate things like in the image below.

I tried to adapt the solution in the aforementioned link, but it doesn't work since the left markings are overwritten when I add more of them.

Does anyone have a solution to this?

--- EDIT ---

This is what I have so far, which works well without nested boxes

\documentclass{article}
\usepackage[a4paper,top=3cm,left=2.5cm,right=2.5cm,bottom=3cm]{geometry}
\usepackage[utf8]{inputenc}
\usepackage{graphicx}
\usepackage{amsmath}
\usepackage{xparse}
\usepackage{calc}
\usepackage{tikz}
\usetikzlibrary{calc}

\newcommand{\tikzmark}[1]{\tikz[overlay,remember picture] \node (#1) {};}
\newcommand{\bitem}[3]{\makebox[#1]{#2\hfill} \quad #3}
\newcommand{\bitemL}[3]{\tikzmark{left}\makebox[#1]{#2\hfill} \quad #3}
\newcommand{\bitemR}[3]{\makebox[#1]{#2\hfill}\tikzmark{right} \quad #3}

\makeatletter
\NewDocumentCommand{\DrawBox}{s O{}}{%
    \tikz[overlay,remember picture]{
    \IfBooleanTF{#1}{%
        \coordinate (RightPoint) at ($(left |- right)+(\linewidth-\labelsep-\labelwidth,0.0)$);
    }{%
        \coordinate (RightPoint) at (right.east);
    }%
    \draw[black]
      ($(left)+(-0.2em,0.9em)$) rectangle
      ($(RightPoint)+(0.2em,-0.3em)$);}
}

\makeatother

\begin{document}

    \medskip\par\noindent
    \begin{minipage}{0.4\linewidth}
        \begin{enumerate}
            \item [1.]{\bitem{2cm}{$\neg Q \rightarrow \neg P$}{$(premissa)$}}
            \item [2.]{\bitemL{2cm}{$P$}{$(hipótese)$}}
            \item [3.]{\bitem{2cm}{$\neg \neg P $}{$(\neg \neg i ~ 2)$}}
            \item [4.]{\bitemR{2cm}{$\neg \neg Q $}{$(MT ~ 1, 3)$}}
            \item [5.]{\bitem{2cm}{$P \rightarrow \neg \neg Q$}{$(\rightarrow i ~ 2,4)$}}
        \end{enumerate}
        \DrawBox[thick]
    \end{minipage}

\end{document}

This code will produce this

Answer 1

I really focus on the boxes here, ignoring nice suggestions like easylist by Symbol 1. This is mainly to advertize the new version of LoopSpaces tikzmark library, which can be found here. This library contains a new command, \tikzmarknode, which can be used to make an ordinary element of some text a node. Amazingly, it will check whether or not you are in math mode, and typeset the text accordingly. You can thus define some nodes and use the fit library to draw boxes around them. These boxes will always contain the nodes, so you may want to set them at some extremal positions. And you can nest these fits, which may help you to have nested boxes, as in the following example. Of course, there is a lot of room for improvement of the layout.

\documentclass{article}
\usepackage{amssymb,tikz}
\usetikzlibrary{tikzmark,fit}
\begin{document}
\begin{enumerate}
 \item \qquad $\tikzmarknode{q1}{q}\to r$ \hfill hypothesis\\[2mm]

 \item \qquad\qquad $\tikzmarknode{neg1}{\neg q\to\neg p}$ \hfill hypothesis\\[2mm]

 \item \qquad\qquad\qquad $\tikzmarknode{p1}{p}$ \hfill hypothesis

 \item \qquad\qquad\qquad $\neg\neg p$ \hfill hypothesis

 \item \qquad\qquad\qquad $\tikzmarknode{neg2}{\neg\neg p}$ \hfill hypothesis\\[2mm]

 \item \qquad\qquad $p\to \tikzmarknode{r2}{r}$ \hfill hypothesis\\[2mm]

 \item \qquad $(\neq p\to \neq q)\to p\to \tikzmarknode{r1}{1}$
\end{enumerate}
\begin{tikzpicture}[overlay,remember picture]
\node[draw,inner sep=9pt,fit=(q1)(r1)]{};
\node[draw,inner sep=9pt,fit=(neg2)(p1)](fit2){};
\node[draw,inner sep=9pt,fit=(neg1)(r2)(fit2)]{};
\end{tikzpicture}
\end{document}