report_header.tex

% \usepackage[T1]{fontenc}
% \usepackage[utf8]{inputenc}
% \usepackage{amsmath,amssymb}
% \usepackage[russian,english]{babel}
\usepackage{fontspec} % loaded by polyglossia, but included here for transparency 
\usepackage{polyglossia}
\setmainlanguage{russian} 
\setotherlanguage{english}
\newfontfamily\russianfont[Script=Cyrillic]{Ubuntu}
% \usepackage{float}
\usepackage{floatrow}
\usepackage{graphicx}