如何在代码中为白色矩形添加如下图所示的阴影效果?
\documentclass[12pt]{article} \usepackage{tikz} \usetikzlibrary{arrows, shapes, positioning} \begin{document} \pagestyle{empty} \pagecolor{blue!50} \begin{tikzpicture}[remember picture, overlay] \fill[fill=white]([xshift=23mm, yshift=-23mm]current page.north west)rectangle([xshift...