~/.config/fontconfig/fonts.conf

fonts.conf

<?xml version='1.0'?>                                                          
<!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>                                       
<fontconfig>                                                                   
 <alias>                                                                       
  <family>serif</family>                                                       
  <prefer>                                                                     
   <family>Times New Roman</family>                                            
  </prefer>                                                                    
 </alias>                                                                      
 <alias>                                                                       
  <family>sans-serif</family>                                                  
  <prefer>                                                                     
   <family>Ubuntu</family>
  </prefer>
 </alias>
 <alias>
  <family>monospace</family>
  <prefer>
   <family>Ubuntu Mono</family>
  </prefer>
 </alias>
 <match target="font">
  <edit mode="assign" name="rgba">
   <const>rgb</const>
  </edit>
 </match>
 <match target="font">
  <edit mode="assign" name="hinting">
   <bool>true</bool>
  </edit>
 </match>
 <match target="font">
  <edit mode="assign" name="hintstyle">
   <const>hintslight</const>
  </edit>
 </match>
 <match target="font">
  <edit mode="assign" name="antialias">
   <bool>true</bool>
  </edit>
 </match>
</fontconfig>