%%%%% timestamp
\startuniqueMPgraphic{Timestamp}
picture p; p := textext("{\ss 2025 年 9 月}");
draw p rotated -45 withcolor darkred;
\stopuniqueMPgraphic
\definelayer[timestamp][width=\paperwidth, height=\paperheight]
\setlayer[timestamp]
         [preset=righttop, hoffset=5mm, voffset=5mm]
         {\uniqueMPgraphic{Timestamp}}
%\setupbackgrounds[page][background=timestamp]

\startstandardmakeup[align=center]
{\tfd \CONTEXT\ 蹊径}
\blank[2*line]
{\tfa 李延瑞（lyr.m2@live.cn）}
\blank[line]
\useURL[ctx-notes][https://github.com/liyanrui/ConTeXt-notes]
项目所在：{\tta\from[ctx-notes]}
\vfill
Copyleft \copyright\  2023 $\sim$ 2025  李延瑞
\blank
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation.
\stopstandardmakeup
\setupbackgrounds[page][background=]