make install.sh non-interactive, set dark mode as default

install.sh

 #/bin/bash
 
+theme="DARK" # one of Dark, Light
 if [ "$(whoami)" != "root" ]
 	then echo "This script is not running as root... exiting" && exit 1
 fi
@@ -34,26 +35,13 @@ fi
 
 cp -rv ./web/* ${installdir}/web/
 
-if [ "$1" != "-u" ]
-	then
-		echo -e "\nTransmission soft theme successfully installed!\n \nWould you like to apply a soft theme now?\nWARNING: if this is an UPDATE you have to skip this!\nNOTE: if you've already installed it, to change theme just modify the " $installdir "/web/index.html following the instructions on the wiki!\n"
-		PS3=': '
-		options=( "Dark" "Light" "Quit" )
-		select opt in "${options[@]}"
-		do
-			case $opt in
-		    "Dark")
+if [ "$1" != "-u" ];then
+    if [[ $theme == "Dark" ]]; then
         sed -i '21i\\t\t<link href="./style/transmission/soft-theme.min.css" type="text/css" rel="stylesheet" />\n\t\t<link href="style/transmission/soft-dark-theme.min.css" type="text/css" rel="stylesheet" />\n' ${installdir}/web/index.html;
         echo "Soft dark theme successfully applied!";
-						break;;
-		    "Light")
+    fi
+    if [[ $theme == "Light" ]]; then
         sed -i '21i\\t\t<link href="./style/transmission/soft-theme.min.css" type="text/css" rel="stylesheet" />\n\t\t<link href="style/transmission/soft-light-theme.min.css" type="text/css" rel="stylesheet" />\n' ${installdir}/web/index.html;
         echo "Soft light theme successfully applied!";
-						break;;
-		     "Quit")
-				 		echo 'You can always install it following the https://git.eigenlab.org/sbiego/transmission-web-soft-theme/wikis/home';
-		        break;;
-		      *) echo 'invalid option'
-					esac
-		done
+    fi
 fi