[gtk, fontconfig] set global font substitutions and use them for gtk

home/.config/fontconfig/conf.d/60-generic.conf

@@ -0,0 +1,39 @@
+<?xml version="1.0"?>
+<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
+<fontconfig>
+  <its:rules xmlns:its="http://www.w3.org/2005/11/its" version="1.0">
+    <its:translateRule translate="no" selector="/fontconfig/*[not(self::description)]"/>
+  </its:rules>
+
+  <description>Set preferable fonts</description>
+	<alias>
+		<family>serif</family>
+		<prefer>
+      <family>Georgia</family>
+      <family>Source Han Serif</family>
+      <family>Source Han Serif SC</family>
+      <family>Source Han Serif TC</family>
+			<family>Source Han Serif K</family>
+		</prefer>
+	</alias>
+	<alias>
+		<family>sans-serif</family>
+    <prefer>
+      <family>Roboto</family>
+      <family>Source Han Sans</family>
+      <family>Source Han Sans SC</family>
+      <family>Source Han Sans TC</family>
+			<family>Source Han Sans K</family>
+		</prefer>
+	</alias>
+	<alias>
+		<family>monospace</family>
+		<prefer>
+			<family>Iosevka sbruder</family>
+      <family>Source Han Sans HW</family>
+      <family>Source Han Sans HW SC</family>
+      <family>Source Han Sans HW TC</family>
+			<family>Source Han Sans HW K</family>
+		</prefer>
+	</alias>
+</fontconfig>

home/.config/gtk-3.0/settings.ini

@@ -1,5 +1,5 @@
 [Settings]
-gtk-font-name=Roboto 10
+gtk-font-name=sans-serif 10
 gtk-theme-name=Adwaita
 gtk-icon-theme-name=Adwaita
 gtk-fallback-icon-theme=gnome

home/.gtkrc-2.0

@@ -1,6 +1,6 @@
 gtk-theme-name="Adwaita"
 gtk-icon-theme-name="Adwaita"
-gtk-font-name="Roboto 10"
+gtk-font-name="sans-serif 10"
 gtk-cursor-theme-name="Adwaita"
 gtk-cursor-theme-size=0
 gtk-toolbar-style=GTK_TOOLBAR_BOTH