Coloring footnotes (mark and text)

Question

(A) In order to make the footnote symbols red, I include the following command in the beginning of my LaTeX documents:

\renewcommand\thefootnote{\textcolor{red}{\fnsymbol{footnote}}}

But what similar thing can I write to make [also] the text in the footnotes red? Have tried myself and googled in vain – Please keep it simple (an explicit command line like the one above) thanks!

\documentclass[a4paper,12pt]{article} 
\usepackage{amsmath, amssymb, amsthm, cite, graphicx, color, setspace} 
\usepackage[usenames,dvipsnames]{xcolor} 
\usepackage[multiple]{footmisc} 
\linespread{1.3} 

\renewcommand\thefootnote{\textcolor{red}{\fnsymbol{footnote}}} 

\usepackage[hmargin=3.2cm,vmargin=4.2cm]{geometry} 
\usepackage{soul} 
\setul{}{4pt} 

\begin{document} 
\title{} 
\date{} 
\setul{}{1pt} 
An example of a number\footnote{Numbers are fun.} is $5.$ 
\end{document}

(B) If I have a folder with hundreds of LeTeX files and I want to include this in all of them (so all of these footnote texts become red), is there any simple way of doing this? I am not good at computers, so please rather write 'no' than something complicated.

Answer 1

For A): You may want to redefine the command \@makefntext as well, which is, however, defined differently depending on the document class you use:

\documentclass[a4paper,12pt]{article} 
\usepackage{xcolor} 

\makeatletter
\renewcommand\thefootnote{\textcolor{red}{\fnsymbol{footnote}}}
\renewcommand\@makefntext[1]{%
  \parindent 1em%
  \noindent
  \hb@xt@1.8em{\hss\@makefnmark}\textcolor{red}{#1}}
\makeatother

\begin{document} 
An example of a number\footnote{Numbers are fun.} is $5$. 
\end{document}