\documentclass{standalone}
\usepackage{fontspec}
\usepackage[export]{adjustbox}
\usepackage[cmyk]{xcolor}
\usepackage{xparse}
\setmainfont{HelveticaNeueLTStd-ThEx}
\newfontfamily\des{HelveticaNeueLTStd-Th}
\newfontfamily\mathematiciens{HelveticaNeueLTStd-Lt}
\ExplSyntaxOn
\tl_new:N \l__gzt_frontmatter_head_text_tl
\tl_set:Nn \l__gzt_frontmatter_head_text_tl {%
  \adjustbox{stack=r}
  {%
    \addfontfeature{LetterSpace=10}
    \textcolor{__gzt_generic_light_color}{%
      \fontsize{21}{0}\selectfont%
      la\hspace{5mm}%
      \fontsize{45}{0}\selectfont%
      Gazette%
    }%
    \\[1.7mm]%
    \fontsize{15}{0}\selectfont%
    \textcolor{__gzt_generic_light_color}{%
      \des%
      \addfontfeature{LetterSpace=6}%
      des%
    }%
    \hspace{2.5mm}%
    \textcolor{__gzt_generic_dark_color}{%
      \mathematiciens%
      \addfontfeature{LetterSpace=6}%
      Math\'ematiciens%
    }%
 }%
}
\NewDocumentCommand \frontmatterheadtext {  } {
  \l__gzt_frontmatter_head_text_tl
}
\definecolorset{cmyk}{__gzt_}{_color}{
  generic_dark,1,.60,.10,0; % kind of blue (!)
  light_generic_dark,1,.35,0,0 % kind of blue (!), light
}
\colorlet{__gzt_generic_light_color}{black!50}
\colorlet{__gzt_dark_generic_light_color}{black!60}
\colorlet{__gzt_description_label_light_color}{__gzt_dark_generic_light_color}
\colorlet{__gzt_cover_itemize_label_color}{__gzt_light_generic_dark_color}
\colorlet{__gzt_default_text_color}{black}
\colorlet{__gzt_rubric_head_text_color}{black!65}
\colorlet{__gzt_bibliography_minibios_acknowledgments_bg_color}{black!10}
\colorlet{__gzt_headrule_color}{__gzt_generic_light_color!65}
\colorlet{__gzt_circlerule_color}{__gzt_generic_dark_color!65}
\colorlet{__gzt_frontmatter_text_color}{black!75}
\colorlet{__gzt_people_color}{__gzt_generic_dark_color}
\colorlet{__gzt_arrayrule_color}{__gzt_generic_dark_color}
\colorlet{__gzt_acknowledgements_color}{__gzt_generic_dark_color}
\colorlet{__gzt_question_color}{__gzt_generic_dark_color}
\colorlet{__gzt_boxed_issue_number_bg_color}{__gzt_generic_dark_color}
\colorlet{__gzt_rule_in_toc_color}{__gzt_generic_dark_color}
\colorlet{__gzt_rubric_in_toc_color}{__gzt_generic_dark_color}
\colorlet{__gzt_article_in_toc_color}{__gzt_generic_light_color}
\colorlet{__gzt_rubric_title_color}{__gzt_generic_light_color}
\colorlet{__gzt_article_title_color}{__gzt_generic_dark_color}
\colorlet{__gzt_section_color}{__gzt_generic_dark_color}
\colorlet{__gzt_subsection_color}{__gzt_generic_dark_color!90}
\colorlet{__gzt_subsubsection_color}{__gzt_generic_dark_color!80}
\colorlet{__gzt_rubric_abstract_color}{__gzt_generic_dark_color}
\colorlet{__gzt_article_abstract_color}{__gzt_generic_light_color}
\colorlet{__gzt_dotfill_color}{__gzt_generic_dark_color}
\colorlet{__gzt_about_frontcover_title_color}{__gzt_generic_dark_color}
\colorlet{__gzt_reflected_text_color}{__gzt_generic_dark_color}
\colorlet{__gzt_inside_frontcover_frame_bg_color}{__gzt_generic_dark_color!8}
\colorlet{__gzt_inside_frontcover_frame_title_color}{__gzt_generic_dark_color}
\colorlet{__gzt_footer_bg_color}{black!10}
\colorlet{__gzt_float_title_color}{__gzt_generic_dark_color}
\colorlet{__gzt_float_title_bg_color}{__gzt_generic_dark_color!10}
\colorlet{__gzt_float_frame_color}{__gzt_generic_dark_color!20}
\colorlet{__gzt_chapter_color}{__gzt_generic_dark_color}
\colorlet{__gzt_smf_number_color}{__gzt_generic_dark_color}
\colorlet{__gzt_date_color}{__gzt_generic_light_color}
\colorlet{__gzt_table_head_color}{__gzt_generic_dark_color!25}
\colorlet{__gzt_book_review_frame_bg_color}{__gzt_generic_dark_color!8}
\colorlet{__gzt_book_advertisement_bg_color}{white}
\colorlet{__gzt_book_advertisement_frame_color}{__gzt_generic_dark_color}
\ExplSyntaxOff
\begin{document}
\frontmatterheadtext
\end{document}

