How can I modify the section style like this?

Question

I found this document with the following section style and header:

I am a true newbie at latex, is there a way I can do something similar? This personalized "section title" and this header, which indicates the section the page belongs to?

(In the 1st image, it says "Chapter 1" and the section is "Introduction") (In the 2nd image, the section "Introduction" is shown at the header)

Thanks!

---- EDIT -----

Question to Alan Xiang

Is there a way to change from

"1.1.1 Some Subsection"

to

"1.1 Some Subsection"

??

Detail: "Chapter 1" is merely decorative, it does not need to be a structure (if that matters).

Thanks!

Answer 1

Fairly simple using memoir:

\documentclass{memoir}
\usepackage[portuguese]{babel}
\usepackage{lipsum}
\chapterstyle{bianchi}
\begin{document}
\chapter{Introduç\~ao}
\section{Some subsection}
\lipsum
\end{document}

Answer 2

If you are using KOMA-Script document classes (which are nice replacements for standard ones like article, report), these questions provide some clue on how to reproduce the title:

• How to make a rule under each section title with KOMA-Script?
• How to center headings at KOMA-Script
• how to add section number and name to the page header

The header can be customized with scrlayer-scrpage package.

The code is as follows:

\documentclass[DIV=10]{scrreprt}
\usepackage[T1]{fontenc}
\usepackage{scrlayer-scrpage}
\usepackage{expl3}
\usepackage{blindtext} % dummy text
\usepackage{mdframed}
\makeatletter
\ExplSyntaxOn
\bool_new:N \l_processed_bool
% redefine section title
\renewcommand{\sectionlinesformat}[4]{
\bool_set_false:N \l_processed_bool

\str_if_eq:nnT {#1} {section} {
    \begin{mdframed}[leftline=false, rightline=false, linewidth=0.8pt, innertopmargin=5mm, innerbottommargin=5mm, leftmargin=1cm, rightmargin=1cm]
    \centering\@hangfrom{\hskip #2}{#4}\par
    \end{mdframed}
    \bool_set_true:N \l_processed_bool
}

\bool_if:nT {!\l_processed_bool} {
    % use default style
    \@hangfrom{\hskip #2#3}{#4}
}


}
% redefine chapter title
\renewcommand{\chapterlinesformat}[3]{
\bool_set_false:N \l_processed_bool

\str_if_eq:nnT {#1} {chapter} {
    \begin{center}
        Chapter~#2
    \end{center}
    \vspace*{-6mm} % reduce spacing
    \bool_set_true:N \l_processed_bool
}

\bool_if:nT {!\l_processed_bool} {
    % use default style
    \@hangfrom{#2}{#3}
}


}
\tl_new:N \l_section_number_tl
% by default, the section numering is chapter.section
% we need to delete the chapter index here
\cs_set:Npn \fix_section_number:n #1 {
    \tl_set:Nx \l_section_number_tl {#1}
    \regex_replace_once:nnN {[0-9]+.} {} \l_section_number_tl
}
% change chapter font
\addtokomafont{chapter}{\normalfont\Large\itshape}
% set header
\chead{}
\renewcommand{\sectionmark}[1]{
    \fix_section_number:n{\thesection}
    \markright{\l_section_number_tl .\ #1}
} 
\ohead{\scshape \rightmark}
\ihead{\pagemark}
% disable page number
\cfoot{}
% activate head sep line
\KOMAoption{headsepline}{0.5pt}
% suppress page numbering on chapter start pages
\let\oldchapter\chapter
\RenewDocumentCommand{\chapter}{om}{
    \IfValueTF{#1}{
        \oldchapter[#1]{#2}
    }{
        \oldchapter{#2}
    }
    \thispagestyle{empty}
}
\ExplSyntaxOff
\makeatother
\begin{document}
    \chapter{Some Chapter}
    \section{Introduction}
    \Blindtext[9]
    \section{More Introduction}
    \Blindtext[8]
\end{document}

Update

If you want to modify subsection styles, you can modify \sectionlinesformat. Everything works properly except from table of contents-more work needs to be done to correct it.

\documentclass[DIV=10]{scrreprt}
\usepackage[T1]{fontenc}
\usepackage{scrlayer-scrpage}
\usepackage{expl3}
\usepackage{blindtext} % dummy text
\usepackage{mdframed}
\makeatletter
\ExplSyntaxOn
\bool_new:N \l_processed_bool
\tl_new:N \l_section_number_tl
% by default, the section numering is chapter.section
% we need to delete the chapter index here
\cs_set:Npn \fix_section_number:n #1 {
    \tl_set:Nx \l_section_number_tl {#1}
    \regex_replace_once:nnN {[0-9]+.} {} \l_section_number_tl
}
% redefine section title
\renewcommand{\sectionlinesformat}[4]{
\bool_set_false:N \l_processed_bool

\str_if_eq:nnT {#1} {section} {
    \begin{mdframed}[leftline=false, rightline=false, linewidth=0.8pt, innertopmargin=5mm, innerbottommargin=5mm, leftmargin=1cm, rightmargin=1cm]
    \centering\@hangfrom{\hskip #2}{#4}\par
    \end{mdframed}
    \bool_set_true:N \l_processed_bool
}
\str_if_eq:nnT {#1} {subsection} {
    \fix_section_number:n {#3}
    \@hangfrom{\hskip #2\l_section_number_tl}{#4}
    \bool_set_true:N \l_processed_bool
}

\bool_if:nT {!\l_processed_bool} {
    % use default style
    \@hangfrom{\hskip #2#3}{#4}
}


}
% redefine chapter title
\renewcommand{\chapterlinesformat}[3]{
\bool_set_false:N \l_processed_bool

\str_if_eq:nnT {#1} {chapter} {
    \begin{center}
        Chapter~#2
    \end{center}
    \vspace*{-6mm} % reduce spacing
    \bool_set_true:N \l_processed_bool
}

\bool_if:nT {!\l_processed_bool} {
    % use default style
    \@hangfrom{#2}{#3}
}


}
% change chapter font
\addtokomafont{chapter}{\normalfont\Large\itshape}
% set header
\chead{}
\renewcommand{\sectionmark}[1]{
    \fix_section_number:n{\thesection}
    \markright{\l_section_number_tl .\ #1}
} 
\ohead{\scshape \rightmark}
\ihead{\pagemark}
% disable page number
\cfoot{}
% activate head sep line
\KOMAoption{headsepline}{0.5pt}
% suppress page numbering on chapter start pages
\let\oldchapter\chapter
\RenewDocumentCommand{\chapter}{som}{
    \IfValueTF{#2}{
        \IfBooleanTF{#1}{
            \oldchapter[#2]{#3}
        } {
            \oldchapter[#2]{#3}
        }
    }{
        \IfBooleanTF{#1}{
            \oldchapter{#3}
        } {
            \oldchapter{#3}
        }
    }
    \thispagestyle{empty}
}
\ExplSyntaxOff
\makeatother
\begin{document}
    \chapter{Some Chapter}
    \section{Introduction}
    \subsection{Subsection}
    \Blindtext[9]
    \section{More Introduction}
    \Blindtext[8]
\end{document}