[Tex/LaTex] beautiful section styles

Question

I came across to website of IREM which I found beautiful section style in the following file Original file was created with PDFLaTeX.

Could someone please create those styles for sections and subsections with Latex

\documentclass{article}
\usepackage[utf8]{inputenc}

\title{Sections and Chapters}
\author{Educ}
\date{\today}

\begin{document}

\maketitle

\section{Plya's Problem-Solving Cycle}
\subsection{Understand the problem}
\subsection{Devise a Plan}
\subsection{Carry Out the Plan}
\subsection{Look Back}
\section{Second Section}


\end{document}

Answer 1

Answer based on titlesec and soul:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{xcolor}
\usepackage[explicit]{titlesec}
\usepackage{soul}

\definecolor{titleblue}{HTML}{4a7aa4}

\title{Sections and Chapters}
\author{Educ}
\date{\today}

\newbox\TitleUnderlineTestBox
\newcommand*\TitleUnderline[1]
  {%
    \bgroup
    \setbox\TitleUnderlineTestBox\hbox{\colorbox{titleblue}\strut}%
    \setul{\dimexpr\dp\TitleUnderlineTestBox-.3ex\relax}{.3ex}%
    \ul{#1}%
    \egroup
  }
\newcommand*\SectionNumberBox[1]
  {%
    \colorbox{titleblue}
      {%
        \makebox[2.5em][c]
          {%
            \color{white}%
            \strut
            \csname the#1\endcsname
          }%
      }%
    \TitleUnderline{\ \ \ }%
  }
\titleformat{\section}
  {\Large\bfseries\sffamily\color{titleblue}}
  {\SectionNumberBox{section}}
  {0pt}
  {\TitleUnderline{#1}}
\titleformat{\subsection}
  {\large\bfseries\sffamily\color{titleblue}}
  {\SectionNumberBox{subsection}}
  {0pt}
  {\TitleUnderline{#1}}

\begin{document}

\maketitle

\section{Plya's Problem-Solving Cycle}
\subsection{Understand the problem}
\subsection{Devise a Plan}
\subsection{Carry Out the Plan}
\subsection{Look Back}
\section{Second Section}

\section
  {Really long section name that is really long, so long it takes two rows}

\end{document}