Update OFFLINE.md

OFFLINE.md

@@ -1,13 +1,30 @@
 # Using Snap! Without an Internet Connection
 
+last updated on Nov. 25, 2021
+
 Snap! is a web application hosted at
 [https://snap.berkeley.edu/run](https://snap.berkeley.edu/run "Snap! online").
-   
-If you would like to use Snap! without being connected to the internet, e.g. in a remote area
-or in a school with limited or unreliable online service you can easily set up Snap! locally on
-your computer, by following these
 
-## Simple Steps:
+If you would like to use Snap! without being connected to the internet, e.g. in a remote area
+or in a school with limited or unreliable online service there are two ways to set up Snap! locally
+on your computer: Either as a "progressive web app" (PWA) or by downloading the sources and opening
+them locally in your browser.
+
+## Installing Snap! as PWA
+
+The easiest way set up Snap! locally on your computer is to open the Snap! IDE in your browser and then to select "install" in the browser's url bar, usually found on the far right. This will let
+you use Snap! just like any other app on your computer, tablet or phone, even if you have no
+internet connection. You will also be able to import costumes, backgrounds, souds and additional
+blocks just like you would if you were online, using the same dialogs and user interface.
+
+Currently the ability to install Snap! as a PWA is supported by Chrome, Edge, Safari on iOS, and Firefox on Android. If you're using one of these browsers, this is the preferred method for you:
+Install once and you're done.
+
+## Downloading Snap!'s Sources
+
+If your preferred web browser does not support PWAs, e.g. if you're using Desktop Firefox, you can still use Snap! offline by following these
+
+### Simple Steps:
 
 1. Download the latest Snap! Release from
 [https://github.com/jmoenig/Snap/releases/latest](https://github.com/jmoenig/Snap/releases/latest "Snap! Source Code"), and unpack the contents of the archive to your local disk.
@@ -18,9 +35,9 @@ Snap! is just a web page, you can open it locally in your browser, no need to in
 on your computer. You can use whichever operating system you like, you don't even need
 admin rights. You can also use a memory stick to distribute the directory with source files
 among the participants of a workshop or the students of your class, even if some of them
-are using MacOS and others run MS Windows or Linux. 
+are using MacOS and others run MS Windows or Linux.
 
-## Remember to Unpack
+### Remember to Unpack
 
 Windows users, this is for you.
 
@@ -30,25 +47,23 @@ to your computer. If you downloaded the zip file please actually unzip it, befor
 on Windows double clicking the zip fie will *not* unzip it but instead show you the contents of
 the archive.
 
-## Which Web Browser?
+### Which Web Browser?
 
-It's best to open Snap! in Chrome or Firefox.
+It's best to open Snap! in Chrome, Edge, Safari or Firefox.
 
 Snap! is using web standards and runs in any modern web browser. Some browsers are faster
 than others, which makes using Snap! more fun. For the best user experience we recommend
-Chrome or Firefox. IE does not comply with modern web standards and will not work. Edge
-will work, but some operations will be so slow it takes the fun out of programming and playing. 
+Chrome or Firefox. IE does not comply with modern web standards and will not work. The new Edge browser is based on Chrome and will work just fine, if you have an old Windows version with an old version of Edge it will also work, but some operations will be so slow it takes the fun out of programming and playing.
 
-## What about Tablets?
+### What about Tablets?
 
-We don't recommend it.
+Snap! works on most modern tablets, but the UI isn't yet optimized for mobile use. Therefore we recommend to use a stylus or "pencil". This makes is much easier to click on small elements like
+input slots, drop-down menus and expansion arrows. If a tablet is your primary computing device
+for programming we also recommend an external Bluetooth keyboard. You'll be able to use Snap!
+with the "soft" keyboard as well, but you might find it getting in the way of other UI elements
+you'd like to see, e.g. blocks or sprites.
 
-Snap! sorta runs on tablets, but the UI isn't optimized for mobile use. Also, many mobile
-web browsers enforce some restrictions that are not web-standards compliant, e.g. they
-will not support the soft keyboard or intentionally slow down certain operations to discourage
-using web apps in favor of proprietary "native" apps.
-
-## Restrictions of the Offline Version
+### Restrictions of the Offline Version
 
 You can't access the cloud, duh. Everything else just works.
 
@@ -57,7 +72,7 @@ file locally there aren't any restrictions. You can use all the blocks, import p
 libraries, take snapshots with the webcom, record sounds with the microphone, draw your
 own costumes etc.
 
-## Saving and Loading
+### Saving and Loading
 
 When you use Snap! locally you will not be able to save projects to the cloud, nor can you
 access projects saved in the cloud. Instead projects will be exported as xml-files to your
@@ -74,7 +89,7 @@ also drag and drop several files all at once.
 
 Easy, isn't it?
 
-## Keeping Snap! up-to-date
+### Keeping Snap! up-to-date
 
 From time to time it's wise to check whether a new version of Snap! is available. You can
 find out the lastest release using the link above, and compare that to the offline sources on