# Background Color for Section Title

I have seen many answers to this question, but all of them seem very complicated and I don't understand how they work at all (copy and pasting them into my code doesn't seem to work either).

I should also add that I'm completely new to this.

All I want is a simple code that takes the default section title in LaTeX

and fills it in to become something like

This is what I currently have:

\documentclass[11pt, oneside]{article}
\usepackage{geometry}
\geometry{a4paper}
\usepackage{graphicx}

\begin{document}

\section{Introduction}

\end{document}


Any help will be much appreciated!

Here is a very simple solution with titlesec:

\documentclass[11pt, oneside]{article}
\usepackage{fourier}
\usepackage{geometry}
\geometry{a4paper}
\usepackage{graphicx}
\usepackage[, x11names]{xcolor}

\usepackage{titlesec}

\titleformat{\section}{\LARGE}{\rlap{\color{Aquamarine1!92!Chartreuse1}\rule[-0.4cm]{\linewidth}{1.2cm}} \thesection}{1em}{}

\begin{document}

\section{Introduction}

\end{document}