\documentclass[11pt]{article}

\usepackage[sans]{myctex}
\usepackage{algo}


\title{思源黑体 + FiraGO}
\author{丛宇}
\date{\today}

\begin{document}
\maketitle

test math font.
\(
G'=(V,E)
\)

测试中文

\textbf{粗中文a}

$\mathbf{Bold Math}$

\section{$Bold \; MATH \Z\R \Q$ in title  $\mathbf{Bold Math \Z \R \Q}$?}
\section{这是bold $\text{你好abc}\R$?}
\begin{theorem}[sbada]
    aaa 中文
\end{theorem}
\begin{proof}
    test setminus and qed $A\setminus B$
\end{proof}

\begin{equation}
\begin{aligned}
\min&   &   \sum_x \delta_x&    &   &\\
s.t.&   &   (1-\delta_x - \delta_y) d^2(x,y)\leq \|v_x-v_y\|^2 &\leq (c^2+(\delta_x+\delta_y)f(k)) d^2(x,y) &   &\forall x,y\in X\\
    &   &   \delta_x\in [0,1], v_x&\in \R^p   &   &\forall x\in X
\end{aligned}
\end{equation}

\begin{figure}
\begin{algo}
sdf\\
\quad sdf\\
return ss
\end{algo}
\caption{this is a fig 这是图}
\end{figure}

\textsc{Small Capital}

\textit{italic}

\texttt{mono}

\end{document}