对于这个问题，我使用以下代码：
\documentclass{article}
\usepackage[utf8x]{inputenc}
\usepackage{concmath}
\usepackage{amsmath}
\usepackage{xcolor}
\usepackage{pagecolor}
\usepackage{fancyhdr}
\definecolor{blueish}{rgb}{0.565,0.886,1} % blue-ish
\definecolor{darkgray}{rgb}{0.15,0.15,0.15} % very dark gray
% ==================================================
\makeatletter
\fancypagestyle{scifi}{%
\fancyhf{}% Clear header/footer
\fancyfoot[C]{\textcolor{blueish}{\thepage}}% Page # in middle/centre of footer
}
\makeatother
% ==================================================
\pagestyle{scifi}
\begin{document}
\pagecolor{darkgray}
\color{blueish}
\title{A test sci-fi document}
\date{2958.16.32}
\maketitle
\reversemarginpar
% -----------------------------------------
\begin{enumerate}
\item How many errors can each of the following codes detect/correct? (assuming NND decoder)
\begin{enumerate}
\item $\mathcal{C} = \{000000, 111111, 000111\}, q = 2$
Computing the minimum distance between any two code words:
\begin{center}
\begin{tabular}{c|c|c|c}
& $000000$ & $111111$ & $000111$ \\
\hline
$000000$ & $0$ & & \\
\hline
$111111$ & $6$ & $0$ & \\
\hline
$000111$ & $3$ & $3$ & $0$ \\
\end{tabular}
\end{center}
Since the minimum distance between code words is $3$:
\begin{align*}
&u \leq d - 1 \\
&u \leq 3 - 1 \\
&u \leq 2 \\
& \\
&v \leq \lfloor\frac{d - 1}{2}\rfloor \\
&v \leq \lfloor\frac{3 - 1}{2}\rfloor \\
&v \leq 1
\end{align*}
So, this code can correct $1$ or less errors, and can detect $2$ or less errors.
\end{enumerate}
\end{enumerate}
\end{document}
它产生如下输出（单击放大）：
很难看清，但是页码以黑色显示在页面底部。
令人惊讶的是，在另一个例子中，当我使用更简单的文本时，页码正如我所希望的那样出现：
\documentclass{article}
% code hijacked from: https://gist.github.com/fgrosse/5807324
\usepackage[utf8x]{inputenc}
\usepackage{concmath}
\usepackage{amsmath}
\usepackage{xcolor}
\usepackage{pagecolor}
\usepackage{fancyhdr}
\definecolor{blueish}{rgb}{0.565,0.886,1} % blue-ish
\definecolor{darkgray}{rgb}{0.15,0.15,0.15} % very dark gray
% ==================================================
\makeatletter
\fancypagestyle{scifi}{%
\fancyhf{}% Clear header/footer
\fancyfoot[C]{\textcolor{blueish}{\thepage}}% Page # in middle/centre of footer
}
\makeatother
% ==================================================
\pagestyle{scifi}
\begin{document}
\pagecolor{darkgray}
\color{blueish}
Hello world.
\end{document}
输出（点击放大）：
另外，由于某种原因，“Hello World”上方出现了一个黑条。
为什么会fancyhdr这样表现？
答案1
与 fancyhdr 没有直接关系，这只是通常的问题\maketitle （\chapter等等）\thispagestyle{plain}，因此您需要使用fancyhdr包来重新定义普通页面样式，或者简单地执行
\maketitle
\thispagestyle{scifi}