Vdots are taller than the rest of text

Question

When I use \vdots within the align environment, its size is bigger than of the rest of characters. I want to get rid of the gap (purple colour on the picture below) or somehow move \vdots upward (\vspace{-Xmm} didn't work at all).

My code is

\documentclass[12pt]{article}
\usepackage{amsfonts, amsmath}
\begin{document}
\begin{align}
    A &= B \nonumber\
      &=  C \nonumber \
      &=  \vdots \nonumber \
      &=  Z \nonumber
\end{align}
\end{document}

which gives you

Cheers!

Answer 1

Taken from the hack here:

\documentclass{article}
\usepackage{amsmath}
\makeatletter
\DeclareRobustCommand{\rvdots}{%
  \vbox{
    \baselineskip4\p@\lineskiplimit\z@
    \kern-\p@
    \hbox{.}\hbox{.}\hbox{.}
  }}
\makeatother

\begin{document}
\begin{align}
    A &= B \nonumber\\
      &=  C \nonumber \\
      &=  \rvdots \nonumber \\
      &=  Z \nonumber
\end{align}
\end{document}