usepackage{amsfonts} %for math symbols R,Z,N etc.
    %usepackage[font=small,labelfont=small]{caption}
     usepackage{graphicx}
     usepackage{amsthm}
     usepackage{amsmath} %eqn references
      usepackage[
            colorlinks=true
            ,breaklinks
             %,ngerman
              ]{hyperref}

     usepackage[hyphenbreaks]{breakurl}
     usepackage{xcolor}
     definecolor{c1}{rgb}{0,0,1} % blue
     definecolor{c2}{rgb}{0,0.3,0.9} % light blue
     definecolor{c3}{rgb}{0.3,0,0.9} % red blue
     definecolor{c4}{rgb}{0,0,0}
     hypersetup{
          linkcolor={c4}, % internal links
          citecolor={c4}, % citations
          urlcolor={c4} % external links/urls
       }

      usepackage[font={small,it}, textfont=it, hang]{caption}
     setlength{captionmargin}{30pt}
     usepackage{lipsum}
      usepackage{mwe}
       usepackage[top=3cm, bottom=1in, left=3cm, right=1in]{geometry}
      %usepackage{fullpage}
      %usepackage[top=2cm, bottom=2cm, left=2.5cm, right=2.5cm]{geometry}


       parindent=12mm  %paragraph indent
       %usepackage{amsmath}
        sloppy %for hyphenless justification
        hyphenation{}
        hyphenpenalty=10000
         exhyphenpenalty=10000
         %usepackage{fancyhdr}

           usepackage{titlesec}

            titleformat{chapter}[display]
             {normalfonthugebfseriesfilcenter}{chaptertitlename
             thechapter}{25mm}{Huge}
              titlespacing*{chapter}{0pt}{75mm}{25mm}

              titlespacing*{name=chapter, numberless}{0pt}{25mm}{25mm}

chapter{Introduction}
                label{intro}
                setcounter{page}{1}
                 pagenumbering{arabic}