chore: deep semantic HTML audit and improvements across all pages

app/[locale]/blog/page.tsx

@@ -58,7 +58,7 @@ export default async function BlogIndex({ params }: BlogIndexProps) {
     <div className="bg-neutral-light min-h-screen">
       {/* Hero Section - Immersive Magazine Feel */}
       <Reveal>
-        <section className="relative h-[50vh] md:h-[70vh] min-h-[400px] md:min-h-[600px] flex items-center overflow-hidden bg-primary-dark">
+        <article className="relative h-[50vh] md:h-[70vh] min-h-[400px] md:min-h-[600px] flex items-center overflow-hidden bg-primary-dark">
           {featuredPost && featuredPost.frontmatter.featuredImage && (
             <>
               <Image
@@ -101,7 +101,7 @@ export default async function BlogIndex({ params }: BlogIndexProps) {
               )}
             </div>
           </Container>
-        </section>
+        </article>
       </Reveal>
 
       <Section className="bg-neutral-light py-12 md:py-28">
@@ -146,7 +146,10 @@ export default async function BlogIndex({ params }: BlogIndexProps) {
             {remainingPosts.map((post, idx) => (
               <Reveal key={post.slug} delay={idx * 100}>
                 <Link href={`/${locale}/blog/${post.slug}`} className="group block">
-                  <Card className="h-full flex flex-col border-none shadow-lg hover:shadow-2xl transition-all duration-500 rounded-2xl md:rounded-3xl overflow-hidden">
+                  <Card
+                    tag="article"
+                    className="h-full flex flex-col border-none shadow-lg hover:shadow-2xl transition-all duration-500 rounded-2xl md:rounded-3xl overflow-hidden"
+                  >
                     {post.frontmatter.featuredImage && (
                       <div className="relative h-48 md:h-72 overflow-hidden">
                         <Image