I am pretty new to LaTeX. I used a template for my paper. The template uses the package "lmodern" as font. The text looks good as expected. However my Chapter/Section/Subsection Headers are not in "lmodern"...
e.g.
This is the interesting part of my preamble:
My Chapters dont have anything else but the actual text in it:
As Ivan brought up in the comments, the scrreport class (which is the Koma-Script version of report) sets all headings to be sans-serif by default.
The manual says that you can change this with
\addtokomafont{part}{\normalfont\bfseries}
\addtokomafont{partnumber}{\normalfont\bfseries}
But there’s also a class option for it.
\documentclass[egregdoesnotlikesansseriftitles]{scrreport}
The name is a TeX.SX inside joke.
scrreport, uses sans serif font for the title of chapters and sections – Ivan Feb 09 '21 at 18:13