feat: port SiteFooter (liên hệ Như Quỳnh) + BackToTopButton

src/app/components/landing/BackToTopButton.tsx

@@ -0,0 +1,68 @@
+"use client";
+
+import { ArrowUp } from "lucide-react";
+import { CSSProperties, useEffect, useState } from "react";
+
+export function BackToTopButton() {
+  const [isVisible, setIsVisible] = useState(false);
+  const [scrollProgress, setScrollProgress] = useState(0);
+
+  useEffect(() => {
+    let frameId: number | null = null;
+
+    const updateScrollState = () => {
+      const scrollTop = window.scrollY;
+      const scrollableHeight = document.documentElement.scrollHeight - window.innerHeight;
+      const nextProgress = scrollableHeight > 0 ? Math.min(100, Math.max(0, (scrollTop / scrollableHeight) * 100)) : 0;
+
+      setIsVisible(scrollTop > 120);
+      setScrollProgress(nextProgress);
+      frameId = null;
+    };
+
+    const requestUpdate = () => {
+      if (frameId === null) {
+        frameId = window.requestAnimationFrame(updateScrollState);
+      }
+    };
+
+    requestUpdate();
+    window.addEventListener("scroll", requestUpdate, { passive: true });
+    window.addEventListener("resize", requestUpdate);
+
+    return () => {
+      window.removeEventListener("scroll", requestUpdate);
+      window.removeEventListener("resize", requestUpdate);
+      if (frameId !== null) {
+        window.cancelAnimationFrame(frameId);
+      }
+    };
+  }, []);
+
+  const handleClick = () => {
+    const prefersReducedMotion = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
+
+    window.scrollTo({
+      top: 0,
+      behavior: prefersReducedMotion ? "auto" : "smooth",
+    });
+  };
+
+  return (
+    <button
+      type="button"
+      aria-label="Lên đầu trang"
+      aria-hidden={!isVisible}
+      onClick={handleClick}
+      className="public-back-to-top"
+      data-visible={isVisible ? "true" : "false"}
+      tabIndex={isVisible ? 0 : -1}
+      style={{ "--scroll-progress": `${scrollProgress}%` } as CSSProperties}
+    >
+      <span className="public-back-to-top-ring" aria-hidden="true" />
+      <span className="public-back-to-top-core">
+        <ArrowUp className="h-5 w-5" strokeWidth={2.2} />
+      </span>
+    </button>
+  );
+}

src/app/components/landing/SiteFooter.tsx

@@ -0,0 +1,49 @@
+import Link from "next/link";
+import { Globe2, Mail, MapPin } from "lucide-react";
+import { navigation } from "@/app/content";
+
+export function SiteFooter() {
+  return (
+    <footer id="contact" className="px-4 pb-8 sm:px-6">
+      <div className="mx-auto grid max-w-7xl gap-8 border-t border-[var(--surface-border)] pt-8 lg:grid-cols-[1.1fr_0.72fr_0.82fr]">
+        <div className="min-w-0">
+          <p className="text-lg font-bold text-[var(--tour-ink)]">VR360 Như Quỳnh</p>
+          <p className="mt-3 max-w-[62ch] text-sm leading-6 text-[var(--muted-foreground)]">
+            Cổng số hóa di tích và không gian văn hóa Xã Như Quỳnh, tỉnh Hưng Yên bằng công nghệ VR360.
+          </p>
+        </div>
+
+        <nav className="grid gap-2 text-sm" aria-label="Liên kết nhanh">
+          <p className="font-bold text-[var(--tour-ink)]">Liên kết nhanh</p>
+          {navigation.map((item) => (
+            <Link key={item.href} href={item.href} className="w-fit text-[var(--muted-foreground)] transition-colors hover:text-[var(--tour-ink)]">
+              {item.label}
+            </Link>
+          ))}
+        </nav>
+
+        <div className="grid gap-3 text-sm leading-6 text-[var(--muted-foreground)] lg:text-right">
+          <p className="font-bold text-[var(--tour-ink)]">Thông tin liên hệ</p>
+          <p className="inline-flex items-center gap-2 lg:justify-end">
+            <MapPin className="h-4 w-4 text-[var(--primary)]" strokeWidth={1.8} />
+            Xã Như Quỳnh, tỉnh Hưng Yên
+          </p>
+          <a
+            href="#"
+            className="inline-flex items-center gap-2 font-semibold text-[var(--tour-ink)] hover:text-[var(--primary)] lg:justify-end"
+          >
+            <Globe2 className="h-4 w-4 text-[var(--primary)]" strokeWidth={1.8} />
+            Cổng thông tin Xã Như Quỳnh
+          </a>
+          <Link href="/lien-he" className="inline-flex items-center gap-2 font-semibold text-[var(--tour-ink)] hover:text-[var(--primary)] lg:justify-end">
+            <Mail className="h-4 w-4 text-[var(--primary)]" strokeWidth={1.8} />
+            Gửi góp ý hoặc tư liệu
+          </Link>
+        </div>
+      </div>
+      <div className="mx-auto mt-8 max-w-7xl border-t border-[var(--surface-border)] pt-5 text-center text-sm font-semibold text-[var(--muted-foreground)]">
+        © 2026 VR360 Di sản Xã Như Quỳnh.
+      </div>
+    </footer>
+  );
+}