Docs for UnifiedPush, update docs for message limit

docs/config.md

@@ -208,7 +208,7 @@ or the root domain:
         ProxyPass / http://127.0.0.1:2586/
         ProxyPassReverse / http://127.0.0.1:2586/
 
-        # Higher than the max message size of 512k 
+        # Higher than the max message size of 4096 bytes
         LimitRequestBody 102400
 
         # Redirect HTTP to HTTPS, but only for GET topic addresses, since we want 
@@ -232,7 +232,7 @@ or the root domain:
         ProxyPass / http://127.0.0.1:2586/
         ProxyPassReverse / http://127.0.0.1:2586/
 
-        # Higher than the max message size of 512k 
+        # Higher than the max message size of 4096 bytes 
         LimitRequestBody 102400
 
         # Redirect HTTP to HTTPS, but only for GET topic addresses, since we want 

docs/publish.md

@@ -866,7 +866,7 @@ but just in case, let's list them all:
 
 | Limit | Description |
 |---|---|
-| **Message length** | Each message can be up to 512 bytes long. Longer messages are truncated. |
+| **Message length** | Each message can be up to 4096 bytes long. Longer messages are truncated. |
 | **Requests** | By default, the server is configured to allow 60 requests at once, and then refills the your allowed requests bucket at a rate of one request per 10 seconds. You can read more about this in the [rate limiting](config.md#rate-limiting) section. |
 | **E-mails** | By default, the server is configured to allow sending 16 e-mails at once, and then refills the your allowed e-mail bucket at a rate of one per hour. You can read more about this in the [rate limiting](config.md#rate-limiting) section. |
 | **Subscription limits** | By default, the server allows each visitor to keep 30 connections to the server open. |

docs/static/css/extra.css

@@ -8,6 +8,12 @@
     width: unset !important;
 }
 
+.md-typeset h4 {
+    font-weight: 500 !important;
+    margin: 0 !important;
+    font-size: 1.1em !important;
+}
+
 .admonition {
     font-size: .74rem !important;
 }

docs/subscribe/phone.md

@@ -81,11 +81,28 @@ The ntfy Android app uses Firebase only for the main host `ntfy.sh`, and only in
 It won't use Firebase for any self-hosted servers, and not at all in the the F-Droid flavor.
 
 ## Integrations
+
+### UnifiedPush
+[UnifiedPush](https://unifiedpush.org) is a standard for receiving push notifications without using the Google-owned
+[Firebase Cloud Messaging (FCM)](https://firebase.google.com/docs/cloud-messaging) service. It puts push notifications 
+in the control of the user. ntfy can act as a **UnifiedPush distributor**, forwarding messages to apps that support it. 
+
+To use ntfy as a distributor, simply select it in one of the [supported apps](https://unifiedpush.org/users/apps/). 
+That's it. It's a one-step installation 😀. If desired, you can select your own [selfhosted ntfy server](../install.md)
+to handle messages. Here's an example with [FluffyChat](https://fluffychat.im/):
+
+<div id="unifiedpush-screenshots" class="screenshots">
+    <a href="../../static/img/android-screenshot-unifiedpush-fluffychat.jpg"><img src="../../static/img/android-screenshot-unifiedpush-fluffychat.jpg"/></a>
+    <a href="../../static/img/android-screenshot-unifiedpush-subscription.jpg"><img src="../../static/img/android-screenshot-unifiedpush-subscription.jpg"/></a>
+    <a href="../../static/img/android-screenshot-unifiedpush-settings.jpg"><img src="../../static/img/android-screenshot-unifiedpush-settings.jpg"/></a>
+</div>
+
+### Automation apps
 The ntfy Android app integrates nicely with automation apps such as [MacroDroid](https://play.google.com/store/apps/details?id=com.arlosoft.macrodroid)
 or [Tasker](https://play.google.com/store/apps/details?id=net.dinglisch.android.taskerm). Using Android intents, you can
 **react to incoming messages**, as well as **send messages**.
 
-### React to incoming messages
+#### React to incoming messages
 To react on incoming notifications, you have to register to intents with the `io.heckel.ntfy.MESSAGE_RECEIVED` action (see
 [code for details](https://github.com/binwiederhier/ntfy-android/blob/main/app/src/main/java/io/heckel/ntfy/msg/BroadcastService.kt)).
 Here's an example using [MacroDroid](https://play.google.com/store/apps/details?id=com.arlosoft.macrodroid)
@@ -127,7 +144,7 @@ Here's a list of extras you can access. Most likely, you'll want to filter for `
 | `tags_map` | *string* | `0=tag1,1=tag2,..` | Map of tags to make it easier to map first, second, ... tag |
 | `priority` | *int (between 1-5)* | `4` | Message [priority](../publish.md#message-priority) with 1=min, 3=default and 5=max |
 
-### Send messages using intents
+#### Send messages using intents
 To send messages from other apps (such as [MacroDroid](https://play.google.com/store/apps/details?id=com.arlosoft.macrodroid)
 and [Tasker](https://play.google.com/store/apps/details?id=net.dinglisch.android.taskerm)), you can 
 broadcast an intent with the `io.heckel.ntfy.SEND_MESSAGE` action. The ntfy Android app will forward the intent as a HTTP