This is pdfTeX, Version 3.14159265-2.6-1.40.20 (TeX Live 2019/Debian) (preloaded format=pdflatex 2024.3.16) 7 MAY 2024 14:46 entering extended mode restricted \write18 enabled. %&-line parsing enabled. **content.tex (./content.tex LaTeX2e <2020-02-02> patch level 2 L3 programming layer <2020-02-14> ! LaTeX Error: Missing \begin{document}. See the LaTeX manual or LaTeX Companion for explanation. Type H for immediate help. ... l.4 \begin{frame}[ t,plain] ? ! Emergency stop. ... l.4 \begin{frame}[ t,plain] You're in trouble here. Try typing to proceed. If that doesn't work, type X to quit. Here is how much of TeX's memory you used: 17 strings out of 481239 522 string characters out of 5920377 236563 words of memory out of 5000000 15384 multiletter control sequences out of 15000+600000 532338 words of font info for 24 fonts, out of 8000000 for 9000 1141 hyphenation exceptions out of 8191 12i,0n,15p,79b,20s stack positions out of 5000i,500n,10000p,200000b,80000s ! ==> Fatal error occurred, no output PDF file produced!