docs: add new NGINX Unit landing cards (#841)

* docs: add new NGINX Unit landing cards

Author: JTorreG

content/unit/_index.md

@@ -1,7 +1,45 @@
 ---
 title: NGINX Unit
-description: A lightweight web app server that combines several layers of the typical application stack into a single component.
+nd-subtitle: A lightweight web app server that combines several layers of the typical application stack into a single component
 url: /nginx-unit/
+nd-landing-page: true
 cascade:
   logo: "NGINX-Unit-product-icon-RGB.png"
----
+nd-content-type: landing-page
+nd-product: NGINX Unit
+---
+
+## About
+
+NGINX Unit is a lightweight and versatile application runtime that provides the essential components for your web application as a single open-source server: running application code (including WebAssembly), serving static assets, handling TLS and request routing.
+
+## Featured content
+
+{{<card-layout>}}
+  {{<card-section showAsCards="true" isFeaturedSection="true">}}
+    {{<card title="Key features" titleUrl="/nginx-unit/keyfeatures/" isFullSize="true" icon="unplug">}}
+      Learn about the key features of NGINX Unit, including its support for multiple languages, security, performance, and more
+    {{</card >}}
+    {{<card title="Installation" titleUrl="/nginx-unit/installation/" isFullSize="true">}}
+      Get started with NGINX Unit by installing it on your system. Find instructions for various platforms and package managers
+    {{</card >}}
+    {{<card title="Configuration" titleUrl="/nginx-unit/configuration/" isFullSize="true">}}
+      Learn how to configure NGINX Unit for your applications
+    {{</card >}}
+  {{</card-section>}}
+{{</card-layout>}}
+
+## Other resources
+
+{{<card-layout>}}
+  {{<card-section showAsCards="true">}}
+
+    {{<card title="How-to guides" titleUrl="/nginx-unit/howto/" isFullSize="true">}}
+      Learn how to resolve various real-life situations and issues that you may experience with Unit
+    {{</card >}}
+    {{<card title="Changelog" titleUrl="/nginx-unit/changes/" isFullSize="true" icon="file-clock">}}
+      See the latest changes and updates in NGINX Unit, including new features, bug fixes, and improvements
+    {{</card >}}
+
+  {{</card-section>}}
+{{</card-layout>}}