template/beamerthemegemini.sty

% Gemini theme
% https://github.com/anishathalye/gemini

% ====================
% Dependencies
% ====================

\RequirePackage{exscale}
\RequirePackage{ragged2e}
\RequirePackage{changepage}
\RequirePackage{fontspec}
\RequirePackage{calc}

% ====================
% Fonts
% ====================

% Prefer local fonts under fonts/ if present; else fallback to system fonts; else DejaVu/Latin Modern
\usefonttheme{professionalfonts}

% Raleway family
\IfFileExists{fonts/Raleway/Raleway-Regular.ttf}{
  \newfontfamily\Raleway[
    Path=fonts/Raleway/,
    UprightFont=*-Regular,
    ItalicFont=*-Italic,
    BoldFont=*-Bold,
    BoldItalicFont=*-BoldItalic,
    Ligatures=TeX
  ]{Raleway}
}{
  \IfFontExistsTF{Raleway}{
    \newfontfamily\Raleway[Ligatures=TeX]{Raleway}
  }{
    \newfontfamily\Raleway[Ligatures=TeX]{DejaVu Sans}
  }
}

% Lato family + main sans font
\IfFileExists{fonts/Lato/Lato-Regular.ttf}{
  \newfontfamily\Lato[
    Path=fonts/Lato/,
    UprightFont=*-Light,
    ItalicFont=*-LightItalic,
    BoldFont=*-Regular,
    BoldItalicFont=*-Italic,
    Ligatures=TeX
  ]{Lato}
  \setsansfont{Lato}[
    Path=fonts/Lato/,
    UprightFont=*-Light,
    ItalicFont=*-LightItalic,
    BoldFont=*-Regular,
    BoldItalicFont=*-Italic
  ]
}{
  \IfFontExistsTF{Lato}{
    \newfontfamily\Lato[Ligatures=TeX]{Lato}
    \setsansfont{Lato}[
      UprightFont=*-Light,
      ItalicFont=*-LightItalic,
      BoldFont=*-Regular,
      BoldItalicFont=*-Italic
    ]
  }{
    \IfFontExistsTF{DejaVu Sans}{
      \setsansfont{DejaVu Sans}[BoldFont=*-Bold, ItalicFont=*-Oblique, BoldItalicFont=*-BoldOblique]
      \newfontfamily\Lato[Ligatures=TeX]{DejaVu Sans}
    }{
      \setsansfont{Latin Modern Sans}
      \newfontfamily\Lato[Ligatures=TeX]{Latin Modern Sans}
    }
  }
}

\setbeamerfont{headline}{family=\Raleway}
\setbeamerfont{headline title}{size=\Huge,series=\bfseries}
\setbeamerfont{headline author}{size=\Large}
\setbeamerfont{headline institute}{size=\normalsize}
\setbeamerfont{block title}{family=\Raleway,size=\large,series=\bfseries}
\setbeamerfont{heading}{family=\Lato,series=\bfseries}
\setbeamerfont{caption}{size=\small}
\setbeamerfont{footline}{family=\Raleway,size=\normalsize}
\setbeamerfont{block body}{size=\normalsize}

% ====================
% Macros
% ====================

\newcommand{\samelineand}{\qquad}

% ====================
% Elements
% ====================

% List
\def\@listi{\leftmargin\leftmargini
\topsep 1ex % spacing before
\parsep 0\p@ \@plus\p@
\itemsep 0.5ex} % spacing between

% Itemize

\setbeamertemplate{itemize item}{\raise0.5ex \hbox{\vrule width 0.5ex height 0.5ex}}
\setbeamertemplate{itemize subitem}{\raise0.3ex \hbox{\vrule width 0.5ex height 0.5ex}}
\setbeamertemplate{itemize subsubitem}{\raise0.2ex \hbox{\vrule width 0.5ex height 0.5ex}}

% Enumerate

\setbeamertemplate{enumerate item}{\insertenumlabel.}
\setbeamertemplate{enumerate subitem}{\insertsubenumlabel.}
\setbeamertemplate{enumerate subsubitem}{\insertsubsubenumlabel.}

% Equation
\setlength\belowdisplayshortskip{2ex}

% Caption
\setbeamertemplate{caption}[numbered]
\setbeamertemplate{caption label separator}[period]
\setlength{\abovecaptionskip}{2ex}
\setlength{\belowcaptionskip}{1ex}

% Bibliography
\setbeamertemplate{bibliography item}[text]

% Navigation
\beamertemplatenavigationsymbolsempty

% ====================
% Components
% ====================

% Heading
\newcommand\heading[1]
{%
  \par\bigskip
  {\usebeamerfont{heading}\usebeamercolor[fg]{heading}#1}\par\smallskip
}

% logo
\newlength{\logoleftwidth}
\setlength{\logoleftwidth}{0cm}
\newlength{\logorightwidth}
\setlength{\logorightwidth}{0cm}
\newlength{\maxlogowidth}  % space on both sides set to maxlogowidth to keep title centered
\setlength{\maxlogowidth}{0cm}

\newcommand{\logoright}[1]{
  \newcommand{\insertlogoright}{#1}
  \settowidth{\logorightwidth}{\insertlogoright}
  \addtolength{\logorightwidth}{10ex}
  \setlength{\maxlogowidth}{\maxof{\logoleftwidth}{\logorightwidth}}
}
\newcommand{\logoleft}[1]{
  \newcommand{\insertlogoleft}{#1}
  \settowidth{\logoleftwidth}{\insertlogoleft}
  \addtolength{\logoleftwidth}{10ex}
  \setlength{\maxlogowidth}{\maxof{\logoleftwidth}{\logorightwidth}}
}

% Headline
\setbeamertemplate{headline}
{
  \begin{beamercolorbox}{headline}
    \begin{columns}
      \begin{column}{\maxlogowidth}
        \vskip5ex
        \ifdefined\insertlogoleft
        \vspace*{\fill}
        \hspace{10ex}
        \raggedright
        \insertlogoleft
        \vspace*{\fill}
        \else\fi
      \end{column}
      \begin{column}{\dimexpr\paperwidth-\maxlogowidth-\maxlogowidth}
        \usebeamerfont{headline}
        \vskip3ex
        \centering
        \ifx \inserttitle \empty \else
        {\usebeamerfont{headline title}\usebeamercolor[fg]{headline title}\inserttitle\\[0.5ex]}
        \fi
        \ifx \beamer@shortauthor \empty \else
        {\usebeamerfont{headline author}\usebeamercolor[fg]{headline author}\insertauthor\\[1ex]}
        \fi
        \ifx \insertinstitute \empty \else
        {\usebeamerfont{headline institute}\usebeamercolor[fg]{headline institute}\insertinstitute\\[1ex]}
        \fi
      \end{column}
      \begin{column}{\maxlogowidth}
        \vskip5ex
        \ifdefined\insertlogoright
        \vspace*{\fill}
        \raggedleft
        \insertlogoright
        \hspace{10ex}
        \vspace*{\fill}
        \else\fi
      \end{column}
    \end{columns}
    \vspace{1ex}
    \ifbeamercolorempty[bg]{headline rule}{}{
      \begin{beamercolorbox}[wd=\paperwidth,colsep=0.5ex]{headline rule}\end{beamercolorbox}
    }
  \end{beamercolorbox}
}

% Block
\setbeamertemplate{block begin}
{
  \begin{beamercolorbox}[colsep*=0ex,dp=2ex,center]{block title}
    \vskip0pt
    \usebeamerfont{block title}\insertblocktitle
    % \vskip-1.25ex
    % \begin{beamercolorbox}[colsep=0.025ex]{block separator}\end{beamercolorbox}
  \end{beamercolorbox}
  {\parskip0pt\par}
  \usebeamerfont{block body}
  \vskip1.0ex
  \begin{beamercolorbox}[colsep*=0ex]{block body}
  \justifying
  \setlength{\parskip}{1ex}
  \vskip-2ex
}
\setbeamertemplate{block end}
{
  \end{beamercolorbox}
  \vskip0pt
  \vspace*{2ex}
}

% Alert Block
\setbeamertemplate{block alerted begin}
{
  \begin{beamercolorbox}[colsep*=0ex,dp=2ex,center]{block alerted title}
    \vskip0pt
    \usebeamerfont{block title}\insertblocktitle
    \vskip-1.25ex
    \begin{beamercolorbox}[colsep=0.025ex]{block alerted separator}\end{beamercolorbox}
  \end{beamercolorbox}
  {\parskip0pt\par}
  \usebeamerfont{block body}
  \vskip1.0ex
  \begin{beamercolorbox}[colsep*=0ex]{block alerted body}
  \justifying
  \begin{adjustwidth}{1ex}{1ex}
  \setlength{\parskip}{1ex}
  \vskip-2ex
}
\setbeamertemplate{block alerted end}
{
  \end{adjustwidth}
  \vskip1ex
  \end{beamercolorbox}
  \vskip0pt
  \vspace*{2ex}
}

% Example Block
\setbeamertemplate{block example begin}
{
  \begin{beamercolorbox}[colsep*=0ex,dp=2ex,center]{block example title}
    \vskip0pt
    \usebeamerfont{block title}\insertblocktitle
    \vskip-1.25ex
    \begin{beamercolorbox}[colsep=0.025ex]{block example separator}\end{beamercolorbox}
  \end{beamercolorbox}
  {\parskip0pt\par}
  \usebeamerfont{block body}
  \vskip1.0ex
  \begin{beamercolorbox}[colsep*=0ex]{block example body}
  \justifying
  \begin{adjustwidth}{1ex}{1ex}
  \setlength{\parskip}{1ex}
  \vskip-2ex
}
\setbeamertemplate{block example end}
{
  \end{adjustwidth}
  \vskip1ex
  \end{beamercolorbox}
  \vskip0pt
  \vspace*{2ex}
}

% Footer
\newcommand{\footercontent}[1]{\newcommand{\insertfootercontent}{#1}}

\setbeamertemplate{footline}{
  \ifdefined\insertfootercontent
  \begin{beamercolorbox}[vmode]{headline}
    \ifbeamercolorempty[bg]{headline rule}{}{
      \begin{beamercolorbox}[wd=\paperwidth,colsep=0.25ex]{headline rule}\end{beamercolorbox}
    }
    \vspace{1.5ex}
    \hspace{\sepwidth}
    \usebeamerfont{footline}
    \centering
    \insertfootercontent
    \hspace{\sepwidth}
    \vspace{1.5ex}
  \end{beamercolorbox}
  \else\fi
}