portico: Add subtitle (for distributed teams).

The CSS had been removed in bb6e6ecaa5.

templates/corporate/hello.html

@@ -3,8 +3,8 @@
 
 {% set PAGE_TITLE = "Zulip — organized team chat" %}
 
-{% set PAGE_DESCRIPTION = "Zulip is an organized team chat app, designed
-  for efficient communication." %}
+{% set PAGE_DESCRIPTION = "Zulip is an organized team chat app for distributed
+  teams of all sizes." %}
 
 {% block customhead %}
 <meta name="viewport" content="width=device-width, initial-scale=1.0" />
@@ -18,6 +18,9 @@
         </div>
         <div class="screen-1">
             <h1>Organized team&nbsp;chat</h1>
+            <div class='h1-subheader'>
+                For distributed teams of all sizes.
+            </div>
             <div class='appshot-1'>
                 <picture>
                     <!-- dark theme is only with webp images, since webp support was at the same time or earlier than prefers-color-scheme https://caniuse.com/?search=prefers-color-scheme https://caniuse.com/webp -->

web/styles/portico/hello.css

@@ -112,6 +112,21 @@ ul {
         z-index: 5;
     }
 
+    .h1-subheader {
+        font-family: var(--font-ops);
+        font-style: normal;
+        font-weight: 350;
+        font-size: 24px;
+        line-height: 142%;
+        text-align: center;
+        font-feature-settings:
+            "pnum" on,
+            "lnum" on;
+        color: hsl(0deg 0% 100%);
+        margin: 0 10px;
+        z-index: 5;
+    }
+
     .appshot-1 {
         display: inline-block;
         margin-top: 20px;