Add announcement bar for Status Network merger with Linea

- Implemented an announcement bar in the Docusaurus configuration to inform users about the upcoming merger of Status Network into Linea, including important dates and links to resources.
- Enhanced CSS styles for the announcement bar to improve visibility and user engagement.

Signed-off-by: yjkellyjoo <yejinkellyjoo@gmail.com>

docusaurus.config.ts

@@ -63,6 +63,14 @@ const config: Config = {
 
   themeConfig: {
     image: 'img/sn-social-card.png',
+    announcementBar: {
+      id: 'linea-merger-may-2026',
+      content:
+        '<strong>Status Network is merging into Linea.</strong> Hoodi testnet (chain ID 374) shuts down on <strong>May 15, 2026</strong> — bridge testnet ETH back to L1 before then.<br /><a target="_blank" rel="noopener noreferrer" href="https://status.network/blog/status-network-merges-with-linea-scaling-gasless-privacy-upstream">Read the announcement</a> · <a target="_blank" rel="noopener noreferrer" href="https://bridge.status.network">Open bridge</a>',
+      backgroundColor: '#7140fd',
+      textColor: '#ffffff',
+      isCloseable: true,
+    },
     navbar: {
       title: 'Status Network Docs',
       logo: {

src/css/custom.css

@@ -595,6 +595,26 @@ div[class*='sidebarViewport'] {
   font-size: 0.9rem;
 }
 
+/* Announcement Bar — larger, more prominent */
+[class*='announcementBar'] {
+  font-size: 1rem !important;
+  font-weight: 500 !important;
+  padding: 0.6rem 1rem !important;
+  min-height: 2.75rem !important;
+}
+
+[class*='announcementBarContent'] {
+  font-size: 1rem !important;
+  line-height: 1.5 !important;
+}
+
+[class*='announcementBarContent'] a {
+  color: #ffffff !important;
+  font-weight: 600 !important;
+  text-decoration: underline !important;
+  text-underline-offset: 2px !important;
+}
+
 /* Footer Enhancements */
 .footer {
   background: rgba(var(--page-background-rgb), 0.95) !important;