\section{Alignment, rules and spacing}
Headers follow the corresponding column unless overridden. With \key{align=auto},
text and graphic columns align left and number columns align right. Column
settings override table settings. Use \key{header align=c} for centered headings.
\begin{demo}{Horizontal alignment and vertically centered text}
\begin{center}
\begin{gradtable}[align=c,header align=c,rules=grid,valign=c,
  text width=30mm,column sep=5pt,row padding=3pt,
  header color=gradbarsBlue!8,rule color=gradbarsBlue!60!black]
  \gradcolumn[align=c]{left}{Column A}
  \gradcolumn[align=c]{center}{Column B}
  \gradcolumn[align=c]{right}{Column C}
  \gradcolumn[type=number,align=c,width=20mm,
    options={precision=0}]{number}{Count}
  \gradrow{Method A,Method A,Method A,120}
  \gradrow{A longer name wraps within the text column,Short,Short,5}
\end{gradtable}
\end{center}
\end{demo}
\key{valign=t|c|b} affects text columns only, using array's p/m/b paragraph boxes.
Use \key{align=l},\key{valign=c} for left-aligned, vertically centered text.

In natural-width mode, column width fixes text wrapping but is a minimum for
number and graphic cells. Graphic width controls the plot, label width controls
the numeric slot, and column width controls the cell. Graphic alignment moves
the complete plot-plus-label cell; numeric labels remain right-aligned internally.
\begin{demo}{A centered score heading and graphic cell}
\begin{center}
\begin{gradtable}[align=c,header align=c,rules=rows,graphic width=28mm,label width=12mm,column sep=8pt,row stretch=1.4]
  \gradcolumn[width=24mm,header align=c]{method}{Method}
  \gradcolumn[type=bar,align=c,width=75mm,
    options={max=100,precision=0}]{score}{Score}
  \gradrow{A,82}
  \gradrow{B,NA}
\end{gradtable}
\end{center}
\end{demo}
\begin{center}
\begin{tabularx}{\linewidth}{@{}c>{\centering\arraybackslash}X@{}}
\toprule
\multicolumn{1}{c}{Option} & \multicolumn{1}{c}{Meaning}\\\midrule
\key{rules=booktabs} & Default: top, header separator and bottom rules.\\
\key{rules=rows} & Also separates data rows horizontally.\\
\key{rules=grid} & Full horizontal/vertical grid and outer border.\\
\key{rules=none} & No table rules.\\
column sep & Horizontal padding per side of a column; default 6pt.\\
row stretch & Positive base row-height multiplier: paper/mono 1.2, report 1.5.\\
row padding & Extra height, default 0pt; does not scale graphics.\\
header color & Report defaults to gradbarsTrack; empty clears the fill.\\
rule color & Default black; local to this table.\\
\bottomrule
\end{tabularx}
\end{center}
Spacing and widths must be nonnegative. Cell alignment does not position the
whole table: use an enclosing group with centering, raggedright or raggedleft.