Theme font could be set by editing ~/.textadept/init.lua >From >[https://foicica.com/textadept/manual.html#Themes](https://foicica.com/textadept/manual.html#Themes)
buffer.set_theme() can also tweak theme properties like font face and font size
without editing the theme file itself:
buffer.set_theme('light', {font = 'Monospace', fontsize = 12})
