\documentclass[14pt]{memoir}
\usepackage{ragged2e}
\usepackage{amssymb}
\usepackage{lipsum}
\usepackage{titlesec}
\usepackage{microtype}
\usepackage{setspace}%espace bin stora
\renewcommand{\baselinestretch}{1.2}%
\usepackage{lmodern}
\usepackage{amsfonts}
\usepackage{amstext}
\usepackage{uncial}
%\usepackage[OT1,euler-digits,euler-hat-accent,OT1,T1]{eulervm}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{mathrsfs}
\usepackage{amsthm}
\usepackage{mathtools}
\usepackage{hyperref}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[french]{babel}
\usepackage[top=2cm, bottom=2cm, left=2cm, right=2cm]{geometry}
\usepackage{enumitem}
\usepackage{csquotes}
\usepackage[x11names]{xcolor}
\usepackage{framed, etoolbox}
\colorlet{framecolor}{VioletRed4}
\colorlet{shadecolor}{LavenderBlush2!60}
\usepackage{thmtools} %
\makeatletter
\define@key{thmdef}{frame}[{}]{%
\thmt@trytwice{}{%
\RequirePackage{framed}%
\RequirePackage{thm-patch}%
\def\FrameCommand{\fcolorbox{framecolor}{shadecolor}}
\addtotheorempreheadhook[\thmt@envname]{%
\begin{framed}}%
\addtotheorempostfoothook[\thmt@envname]{\end{framed}}%
}%
}
\makeatother
\usepackage{thmtools}
\declaretheoremstyle[
spaceabove=-6pt,
spacebelow=6pt,
headfont=\normalfont\bfseries,
bodyfont = \normalfont,
postheadspace=1em,
qed=$\blacksquare$,
headpunct={:}]{myproofstyle} %<---- change this name
\declaretheorem[name={Proof}, style=myproofstyle, unnumbered]{Proof}
\declaretheoremstyle[
spaceabove=3pt,
spacebelow=3pt,
headfont=\bfseries,
notefont=\normalfont,
notebraces={(}{)},
bodyfont=\itshape,
postheadspace=1em,
headpunct={:}]{mystyle}
\declaretheoremstyle[
spaceabove=6pt,
spacebelow=6pt,
headfont=\normalfont\bfseries,
notefont=\mdseries\bfseries,
notebraces={({)}},
bodyfont=\normalfont,
postheadspace=1em,
postheadhook = {\hspace{0mm}},%
headpunct={:},]{myst}
\declaretheorem[frame,name={Théorème}, style=mystyle,numberwithin=section]{thm}
\declaretheorem[frame,name={Lemme}, style=mystyle,numberwithin=section]{lema}
\declaretheorem[frame,name={Définition}, style=mystyle,numberwithin=section]{defi}
\declaretheorem[frame,name={Corollaire}, style=mystyle,numberwithin=section]{coro}
\declaretheorem[frame,name={Proposition}, style=mystyle,numberwithin=section]{props}
\declaretheorem[frame,name={Vocabulaire}, style=mystyle,numberwithin=section]{voc}
\declaretheorem[name={Preuve}, style=myst,numbered=no]{preuve}
\declaretheorem[name={Remarque}, style=myst,numberwithin=section]{remark}
\declaretheorem[name={Remarques}, style=myst,numberwithin=section]{remarks}
\declaretheorem[name={Exemple}, style=myst,numberwithin=section]{exemple}
\declaretheorem[name={Exemples}, style=myst,numberwithin=section]{exemples}
\declaretheorem[name={Méthode}, style=mystyle,numberwithin=section]{methode}
\declaretheorem[name={Méthodes}, style=mystyle,numbered=no]{methodes}
\declaretheorem[name={Notation}, style=mystyle,numbered=no]{notation}
\AtBeginEnvironment{defi}{\colorlet{framecolor}{black}
\colorlet{shadecolor}{orange!15}}
\newcommand{\myarrow}[1][1cm]{\mathrel{%
\hbox{\rule[\dimexpr\fontdimen22\textfont2-.2pt\relax]{#1}{.4pt}}%
\mkern-4mu\hbox{\usefont{U}{lasy}{m}{n}\symbol{41}}}}
\AtBeginEnvironment{voc}{\colorlet{framecolor}{black}
\colorlet{shadecolor}{LightSkyBlue2!25}}
\AtBeginEnvironment{props}{\colorlet{framecolor}{black}
\colorlet{shadecolor}{Yellow1!15}}
\AtBeginEnvironment{coro}{\colorlet{framecolor}{black}
\colorlet{shadecolor}{Yellow1!15}}
\AtBeginEnvironment{lema}{\colorlet{framecolor}{black}
\colorlet{shadecolor}{Yellow1!15}}
\AtBeginEnvironment{thm}{\colorlet{framecolor}{black}
\colorlet{shadecolor}{Yellow1!15}}
\makeatletter
%\setbox0\hbox{$\xdef\scriptratio{\strip@pt\dimexpr
% \numexpr(\sf@size*65536)/\f@size sp}$}
\newcommand{\myscriptarrow}[1][1cm]{{%
\hbox{\rule[\scriptratio\dimexpr\fontdimen22\textfont2-.2pt\relax]
{\scriptratio\dimexpr#1\relax}{\scriptratio\dimexpr.4pt\relax}}%
\mkern-4mu\hbox{\let\f@size\sf@size\usefont{U}{lasy}{m}{n}\symbol{41}}}}
\makeatother
\newcommand*{\QED}{\hfill\ensuremath{\blacksquare}}%Heron
\usepackage{dsfont}
\usepackage{enumitem}
\usepackage{textcomp}
\usepackage{tikz, tikz-cd}
\usepackage{amssymb}
\begin{document}
\end{document}
目标是：
答案1
将相关部分添加fontmath.ltx到文档前言中，并进行一些修改。
\documentclass{article}
\DeclareSymbolFont{sansletters}{\encodingdefault}{\sfdefault}{m}{n}
\SetSymbolFont{sansletters}{bold}{\encodingdefault}{\sfdefault}{bx}{n}
\DeclareSymbolFontAlphabet{\mathsf}{sansletters}
\DeclareMathSymbol{A}{\mathalpha}{sansletters}{`A}
\DeclareMathSymbol{B}{\mathalpha}{sansletters}{`B}
\DeclareMathSymbol{C}{\mathalpha}{sansletters}{`C}
\DeclareMathSymbol{D}{\mathalpha}{sansletters}{`D}
\DeclareMathSymbol{E}{\mathalpha}{sansletters}{`E}
\DeclareMathSymbol{F}{\mathalpha}{sansletters}{`F}
\DeclareMathSymbol{G}{\mathalpha}{sansletters}{`G}
\DeclareMathSymbol{H}{\mathalpha}{sansletters}{`H}
\DeclareMathSymbol{I}{\mathalpha}{sansletters}{`I}
\DeclareMathSymbol{J}{\mathalpha}{sansletters}{`J}
\DeclareMathSymbol{K}{\mathalpha}{sansletters}{`K}
\DeclareMathSymbol{L}{\mathalpha}{sansletters}{`L}
\DeclareMathSymbol{M}{\mathalpha}{sansletters}{`M}
\DeclareMathSymbol{N}{\mathalpha}{sansletters}{`N}
\DeclareMathSymbol{O}{\mathalpha}{sansletters}{`O}
\DeclareMathSymbol{P}{\mathalpha}{sansletters}{`P}
\DeclareMathSymbol{Q}{\mathalpha}{sansletters}{`Q}
\DeclareMathSymbol{R}{\mathalpha}{sansletters}{`R}
\DeclareMathSymbol{S}{\mathalpha}{sansletters}{`S}
\DeclareMathSymbol{T}{\mathalpha}{sansletters}{`T}
\DeclareMathSymbol{U}{\mathalpha}{sansletters}{`U}
\DeclareMathSymbol{V}{\mathalpha}{sansletters}{`V}
\DeclareMathSymbol{W}{\mathalpha}{sansletters}{`W}
\DeclareMathSymbol{X}{\mathalpha}{sansletters}{`X}
\DeclareMathSymbol{Y}{\mathalpha}{sansletters}{`Y}
\DeclareMathSymbol{Z}{\mathalpha}{sansletters}{`Z}
\begin{document}
$ABCDEF$ $\mathrm{A}$ $\mathnormal{A}$
\end{document}
大写字母被声明为属于sansletters数学符号字体。在特定情况下，您仍然可以使用或类似方法覆盖排版\mathrm。
如果需要粗体无衬线字母，则不能使用\mathbf。而是加载bm包（之后amsmath）并使用\bm{A}粗体无衬线 A。
