Add banner advertising Solid26, Solid Symposium and Solid Hackathon

Co-authored-by: jeswr <63333554+jeswr@users.noreply.github.com>
Agent-Logs-Url: https://github.com/solid/solidproject.org/sessions/d2a8934d-61ee-4fc7-b8fa-2b4b43fd5a0c

Author: Copilot

_layouts/default.html

@@ -34,7 +34,10 @@
         <span></span>
         <span></span>
       </button>
-    </header>{% if page.breadcrumbs %}
+    </header>
+    <div class="event-banner" role="region" aria-label="Event announcement">
+      📣 Join us for <a href="https://solid26.org/">Solid26</a> — Solid Symposium (Apr 30 – May 1) · Solid Hackathon (Apr 27 – 29) · London, 2026
+    </div>{% if page.breadcrumbs %}
     <nav class="breadcrumb" aria-label="breadcrumbs">
       <ol>
         <li><a href="/">Home</a></li>

assets/css/banner.css

@@ -0,0 +1,20 @@
+/* Event Banner */
+.event-banner {
+    background-color: #7C4DFF;
+    color: #fff;
+    text-align: center;
+    padding: 0.6rem 1rem;
+    font-size: 1rem;
+    line-height: 1.4;
+}
+
+.event-banner a {
+    color: #fff;
+    text-decoration: underline;
+    font-weight: bold;
+}
+
+.event-banner a:hover,
+.event-banner a:focus {
+    color: #e0d4ff;
+}

assets/css/styles.css

@@ -1,4 +1,4 @@
 ---
 permalink: /assets/styles.css
 ---
-{% capture css %}{% include_relative base.css %}{% include_relative header.css %}{% include_relative footer.css %}{% include_relative breadcrumb.css %}{% include_relative homepage.css %}{% include_relative apps.css %}{% endcapture %}{{ css | strip_newlines | replace: '   ', ' ' | replace: '  ', ' ' }}
+{% capture css %}{% include_relative base.css %}{% include_relative header.css %}{% include_relative banner.css %}{% include_relative footer.css %}{% include_relative breadcrumb.css %}{% include_relative homepage.css %}{% include_relative apps.css %}{% endcapture %}{{ css | strip_newlines | replace: '   ', ' ' | replace: '  ', ' ' }}