Text Formatting ⇒ Boxed theorem tex

[latex program]

Good morning
I want boxed-theorem such that theorems must be enumerated by sections, I found this code,I and I tried to do changes in order to enumerate theorems by sections but it didn't work!
\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\usepackage{boiboites}
\newboxedtheorem [ boxcolor=pink, background=white!5, titlebackground=pink!20,
titleboxcolor= black]{Theorem}{Theorem}
\begin{document}
\section{title}
\begin{Theorem}[Loi des grands nombres]
Soit $(X_n)_{n\in \mathbb{N}}$ une suite de variables aléatoires réelles
indépendantes identiquement distribuées telles que $X_1 \in L^1$. Alors :
\[\frac{1}{n} \sum_{i=1}^n X_i \overset{\textnormal{p.s.}}{\longrightarrow}
\mathbb{E} (X_1) .\]
\end{Theorem}
\end{document

[Ijon Tichy]

If this is the package by Alexis Flesch and you want to reset the counter at every section, see his documentation page. There you can find

As for the options, there are a few. For example, thcounter=section will have your environment's counter go back to 0 whenever you enter a new section in your document: …

Disclaimer: I've never used this package, because it is not part of TeX Live and AFAIK not at CTAN and it even does not have a license statement. I would use tcolorbox instead. BTW: The author of boiboites himself recommend to use xeboiboites instead of boiboites:

Please consider trying xeboiboites.sty (still under development but with a lot more features !).

BTW: Please try to mark your code as code. This can be done easily by selecting it and clicking to the Code-Button in the toolbar.

[latex program]

Thank you so much for your answer! I have already used the tcolorbox package but I always get errors because of this package!!!!!!

[Ijon Tichy]

I think we would be able to fix most of such errors, if you'd ask a proper question …

BTW: If you use boiboites in a question you should always add a link to the package. The cost to find a package, that cannot be found on CTAN and is not part of TeX Live and MiKTeX, could deter helpers.

[latex program]

okey! the package boiboites found as a file attachement in https://www.alexisfles.ch/en/latex/boites1.html