colortcolorbox
I am using MikTeX 2.9 on Windows 8.1. The PDF output of the Following TeX file does not display the word "example" in fore color or background color. I'm using TeXWorks editor – that comes with MikTeX – to generate the PDF:
\documentclass{article}
\begin{document}
This is an {\color{green}example} of fore color text.
This is an \colorbox{green}{example} of highlighted text.
\end{document}
Knuth in the TeXBook gave an example of "poor man's bold," (The TeXbook, p. 386) which can be typeset obtained by overprinting the normal weight symbol with slight offsets.
As he says:
The results are somewhat fuzzy, and they certainly are no match for the real thing if it's available; but poor man's bold is better than nothing, and once in a while you can get away with it.
Here, one can use a similar technique and the code is shown below:
\documentclass{article}
\usepackage{graphicx,xcolor}
\usepackage{amsmath}
\def\PoorManContour#1#2#3{\leavevmode
\setbox0=\hbox{{#1}}%
\color{#3}\kern-.002em\copy0\kern-\wd0
\color{#3}\raise-.04em\copy0\kern-\wd0
\color{#3}\lower.04em\copy0\kern-\wd0
\color{#3}\raise0.04em\copy0\kern-\wd0
\color{#2}\raise-.012em\copy0\kern-\wd0
\color{#2}\kern.06em\copy0\kern-\wd0
\color{blue}\kern-.020em\lower.003em\box0
}
\begin{document}
\colorbox{gray!5}{\scalebox{5}{\PoorManContour{$\sqrt{\dfrac{A^3_i}{B^2}}$}{gray!60}{gray!60}}}
\end{document}
To achieve the best results possible one has to kern in small steps for possibly twenty steps or so. For simplicity, I have not done that. In the final version, you need to adjust the colors to suit, possibly changing the shading to white.
Edit
After reading Jan's comment below I read the manual and true, as the commenter said the easiest way to achieve what the OP wanted is to include the package without an option i.e., \usepackage{contour}. Helps to RFM!
I think this question about highlighting in LaTeX is what you are looking for.
Best Answer
add
to the preamble