refactor(home): redesign hackathon top bar with aurora gradient style

pages/index.tsx

@@ -1,5 +1,5 @@
 import { observer } from 'mobx-react';
-import { FC, useContext } from 'react';
+import { CSSProperties, FC, useContext, useEffect, useState } from 'react';
 import { Card, Col, Row } from 'react-bootstrap';
 import { renderToStaticMarkup } from 'react-dom/server';
 import ReactTyped from 'react-typed-component';
@@ -8,13 +8,82 @@ import { PageHead } from '../components/Layout/PageHead';
 import { I18nContext } from '../models/Translation';
 import styles from '../styles/Home.module.less';
 
+// Temporarily disable localStorage persistence so the bar returns after refresh.
+// const HackathonTopBarStorageKey = 'labor-ai-hackathon-2026-top-bar-dismissed';
+const HackathonTopBarLink = '/hackathon/Labor-AI-hackathon-2026';
+
 const HomePage: FC = observer(() => {
   const { t } = useContext(I18nContext);
+  const [isHackathonTopBarVisible, setIsHackathonTopBarVisible] = useState(true);
+  const [hackathonTopBarStyle, setHackathonTopBarStyle] = useState<CSSProperties>();
+
+  // useEffect(() => {
+  //   setIsHackathonTopBarVisible(localStorage.getItem(HackathonTopBarStorageKey) !== 'true');
+  // }, []);
+  useEffect(() => {
+    const navbar = document.querySelector('nav');
+    const syncTopBarOffset = () => {
+      const navbarHeight = navbar?.getBoundingClientRect().height || 56;
+
+      setHackathonTopBarStyle({
+        '--hackathon-top-bar-gap': `${Math.max(navbarHeight - 56, 0)}px`,
+        '--hackathon-top-bar-offset': `${navbarHeight}px`,
+      } as CSSProperties);
+    };
+    const observer =
+      typeof ResizeObserver === 'undefined' || !navbar
+        ? undefined
+        : new ResizeObserver(syncTopBarOffset);
+
+    syncTopBarOffset();
+    if (navbar) observer?.observe(navbar);
+    window.addEventListener('resize', syncTopBarOffset);
+
+    return () => {
+      observer?.disconnect();
+      window.removeEventListener('resize', syncTopBarOffset);
+    };
+  }, []);
+
+  const closeHackathonTopBar = () => {
+    setIsHackathonTopBarVisible(false);
+    // localStorage.setItem(HackathonTopBarStorageKey, 'true');
+  };
 
   return (
     <>
       <PageHead />
 
+      {isHackathonTopBarVisible && (
+        <aside
+          className={styles.hackathonTopBar}
+          aria-label={t('home_hackathon_top_bar_aria_label')}
+          style={hackathonTopBarStyle}
+        >
+          <div className={styles.hackathonTopBarInner}>
+            <a className={styles.hackathonTopBarContent} href={HackathonTopBarLink}>
+              <span className={styles.hackathonTopBarText}>
+                <strong>{t('home_hackathon_top_bar_title')}</strong>
+                <span>{t('home_hackathon_top_bar_description')}</span>
+              </span>
+              <span className={styles.hackathonTopBarEventName}>Labor AI Hackathon 2026</span>
+              <span className={styles.hackathonTopBarAction}>
+                {t('home_hackathon_top_bar_action')}
+              </span>
+            </a>
+            <button
+              className={styles.hackathonTopBarClose}
+              type="button"
+              aria-label={t('home_hackathon_top_bar_close')}
+              title={t('home_hackathon_top_bar_close')}
+              onClick={closeHackathonTopBar}
+            >
+              ×
+            </button>
+          </div>
+        </aside>
+      )}
+
       <section
         className={`flex-fill d-flex flex-column justify-content-center align-items-center bg-secondary bg-gradient text-dark bg-opacity-10 ${styles.main}`}
       >