niri: set background and toggle (dark/light)

niri/.config/niri/config.kdl

@@ -32,6 +32,7 @@ output "DP-1" {
 
 layout {
     gaps 16
+    background-color "#414853"
 
     center-focused-column "never"
 

xsession/bin/lupan-set-theme

@@ -12,9 +12,11 @@ fi
 
 if [ "$THEME" = dark ]; then
     GTK_THEME=Arc-Dark
+    BG_COLOR='#414853'
     rm -f ~/.lightmode
 elif [ "$THEME" = light ]; then
     GTK_THEME=Arc-Light
+    BG_COLOR='#c0c1c2'
     touch ~/.lightmode
 else
     echo "error: unknown theme: should be either dark, light or toggle" >&2
@@ -44,7 +46,6 @@ if [ -f "$ATOML" ]; then
     sed -i "s#^import =.*#import = [\"~/.config/alacritty/$THEME.toml\"]#" "$ATOML"
 fi
 
-XSET=$(readlink -e ~/.config/xsettingsd/xsettingsd.conf)
 if [ "$THEME" = dark ]; then
     kitten themes --reload-in=all 'five-colors-dark'
 elif [ "$THEME" = light ]; then
@@ -52,12 +53,19 @@ elif [ "$THEME" = light ]; then
 fi
 
 # GTK
+XSET=$(readlink -e ~/.config/xsettingsd/xsettingsd.conf)
 if [ -n "$XSET" ]; then
     sed -i -E "s#(Net/ThemeName) .*#\\1 \"${GTK_THEME}\"#" "$XSET"
     pkill -HUP -x xsettingsd
     gsettings set org.gnome.desktop.interface gtk-theme "${GTK_THEME}"
 fi
 
+# niri
+NIRI=$(readlink -e ~/.config/niri/config.kdl)
+if [ -n "$NIRI" ]; then
+    sed -i -E "s%^( *background-color) .*%\\1 \"${BG_COLOR}\"%" "$NIRI"
+fi
+
 # waybar
 WCSS=$(readlink -e ~/.config/waybar/style.css)
 if [ -f "$WCSS" ]; then