1

It seems like I can't change the background color, here is my header and my tests (none changes the background color of the slide, I manage only to change the color of the text):

    \documentclass[aspectratio=169]{beamer}
    \usepackage[T1]{fontenc}
    \usepackage[utf8]{inputenc}
    \usepackage{biolinum}
    \usepackage{microtype}
    \usefonttheme[onlymath]{serif}
    \usetheme[nofirafonts]{focus}


\begin{document}

    \setbeamercolor{background canvas}{bg=black}
    \begin{frame}{Test}
    \textcolor{white}{black} **here it changes only the text color**
    \end{frame}
    
    \setbeamertemplate{background canvas}{}
    \setbeamercolor{background canvas}{bg=red}
    \begin{frame}{Test 2 }   
    Test             ** nothing changes from a standard slide **
    \end{frame}

\end{document}
4

Beamer theme focus draws a background in color normal text.bg, so your change to color background canvas.bg has no effect. In the following example, the used color is changed to background canvas.bg.

\documentclass[aspectratio=169]{beamer}
\usetheme[nofirafonts]{focus}

% redefine beamer template "background canvas" with option "focus"
% originally defined in beamerouterthemefocus.sty
\expandafter\let\csname beamer@@tmpop@background canvas@focus\endcsname\relax
\defbeamertemplate{background canvas}{focus}{%
    \begin{tikzpicture}
        \clip (0,0) rectangle ++(\paperwidth,\paperheight);
        % use color "background cavas.bg" instead of "normal text.bg"
        \fill[background canvas.bg] (0,0) rectangle ++(\paperwidth,\paperheight);
    \end{tikzpicture}%
}

\begin{document}

    \setbeamercolor{background canvas}{bg=black}
    \begin{frame}{Test}
    \textcolor{white}{black} **here it changes only the text color**
    \end{frame}

    \setbeamercolor{background canvas}{bg=red}
    \begin{frame}{Test 2 }   
    Test             ** nothing changes from a standard slide **
    \end{frame}

\end{document}

enter image description here

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.