fix(pagespeed): fix heading inconsistency reported in pagespeed.web.dev

Author: eric15342335

src/components/events/poster-toggle.tsx

@@ -53,6 +53,8 @@ export function PosterToggle({ posters, initialLanguageCode, alt, className }: P
         width={0}
         height={0}
         sizes="100vw"
+        loading="lazy"
+        fetchPriority="high"
         className="h-auto w-full"
       />
     </div>

src/components/sections/footer.tsx

@@ -12,7 +12,7 @@ export function Footer() {
         <div className="mx-auto max-w-4xl">
           <div className="grid gap-8 text-left md:grid-cols-2 md:justify-items-center">
             <div className="flex flex-col items-center space-y-4 md:items-start">
-              <h3 className="font-semibold">Sitemap</h3>
+              <h2 className="font-semibold">Sitemap</h2>
               <ul className="grid grid-cols-2 gap-x-8 gap-y-2">
                 {siteConfig.mainNav.map((link) => (
                   <li key={link.href}>
@@ -27,7 +27,7 @@ export function Footer() {
               </ul>
             </div>
             <div className="flex flex-col items-center space-y-4">
-              <h3 className="font-semibold">Connect with us!</h3>
+              <h2 className="font-semibold">Connect with us!</h2>
               <SocialLinks
                 variant="footer"
                 className="flex flex-col items-start gap-3"

src/components/sections/whats-happening.tsx

@@ -36,7 +36,7 @@ export function WhatsHappening({ events }: { events: WhatsHappeningEvent[] }) {
               />
             </div>
             <div className="flex flex-1 flex-col space-y-2">
-              <h3 className="text-2xl font-semibold">{event.title}</h3>
+              <h2 className="text-2xl font-semibold">{event.title}</h2>
               <p className="text-muted-foreground">{event.description}</p>
               <div className="mt-auto pt-2">
                 <AnimatedFillButton

src/content/events/restage-of-rape-of-nanking.mdx

@@ -34,14 +34,14 @@ import { siteConfig } from "@/lib/config";
     }
   />
 
-<PosterToggle
-  posters={[
-    { code: "en", label: "English", src: "/event/2025-12-13/poster.en.png" },
-    { code: "zh", label: "中文", src: "/event/2025-12-13/poster.zh.png" },
-  ]}
-  initialLanguageCode="en"
-  alt={frontmatter.title + " event poster"}
-/>
+  <PosterToggle
+    posters={[
+      { code: "en", label: "English", src: "/event/2025-12-13/poster.en.png" },
+      { code: "zh", label: "中文", src: "/event/2025-12-13/poster.zh.png" },
+    ]}
+    initialLanguageCode="en"
+    alt={frontmatter.title + " event poster"}
+  />
 
   <div className="grid gap-6 sm:grid-cols-3">
     <AnimatedFillButton