答案1
您可以使用tcolorbox
:
\documentclass{article}
\usepackage[most]{tcolorbox}
\usepackage{lipsum} % for dummy text
\newtcolorbox{mybox}{enhanced,
boxrule=0pt,
frame hidden,
borderline west={4pt}{0pt}{blue!25!white},
colback=white,
sharp corners,
right=0pt,
top=0pt,
bottom=0pt}
\begin{document}
\lipsum[2]
\begin{mybox}
\lipsum[1-2]
\end{mybox}
\lipsum[2]
\end{document}