diff --git a/src/app/wiki/[slug]/wiki-by-slug-client.tsx b/src/app/wiki/[slug]/wiki-by-slug-client.tsx
index e39c2a5..3b59091 100644
--- a/src/app/wiki/[slug]/wiki-by-slug-client.tsx
+++ b/src/app/wiki/[slug]/wiki-by-slug-client.tsx
@@ -156,9 +156,25 @@ export default function WikiBySlugClient({ slug }: { slug: string }) {
   const [renderHtml, setRenderHtml] = useState<string>("");
   const [toc, setToc] = useState<TocItem[]>([]);
   const [activeHeadingId, setActiveHeadingId] = useState<string | null>(null);
+  const [linkPreview, setLinkPreview] = useState<{
+    slug: string;
+    top: number;
+    left: number;
+    width: number;
+    height: number;
+    visible: boolean;
+  } | null>(null);
+  const [linkPreviewData, setLinkPreviewData] = useState<{
+    slug: string;
+    title: string;
+    quote: string | null;
+    status: "idle" | "loading" | "ready" | "error";
+  } | null>(null);
 
   const normalizedSlug = useMemo(() => String(slug || "").trim(), [slug]);
   const contentRootRef = useRef<HTMLDivElement | null>(null);
+  const hidePreviewTimerRef = useRef<number | null>(null);
+  const previewCacheRef = useRef<Map<string, { title: string; quote: string | null }>>(new Map());
 
   // Load wiki data by slug.
   useEffect(() => {
@@ -256,6 +272,158 @@ export default function WikiBySlugClient({ slug }: { slug: string }) {
     return () => obs.disconnect();
   }, [toc]);
 
+  // Hover preview for internal wiki links (title + first blockquote).
+  useEffect(() => {
+    const root = contentRootRef.current;
+    if (!root) return;
+    if (typeof window === "undefined") return;
+
+    const clearHideTimer = () => {
+      if (hidePreviewTimerRef.current != null) {
+        window.clearTimeout(hidePreviewTimerRef.current);
+        hidePreviewTimerRef.current = null;
+      }
+    };
+
+    const hideSoon = () => {
+      clearHideTimer();
+      hidePreviewTimerRef.current = window.setTimeout(() => {
+        setLinkPreview((prev) => (prev ? { ...prev, visible: false } : prev));
+      }, 140);
+    };
+
+    const resolveInternalWikiSlug = (href: string): string | null => {
+      const h = href.trim();
+      if (!h.length) return null;
+      if (h === "__missing__") return null;
+      if (h.startsWith("#")) return null;
+
+      const stripQueryHash = (s: string) => {
+        const m = s.match(/^([^?#]+)([?#].*)?$/);
+        return String(m?.[1] || "");
+      };
+
+      if (h.startsWith("/wiki/")) {
+        const path = stripQueryHash(h);
+        const slugPart = path.slice("/wiki/".length).trim();
+        return slugPart ? decodeURIComponent(slugPart) : null;
+      }
+
+      const originPrefix = window.location.origin + "/wiki/";
+      if (h.startsWith(originPrefix)) {
+        const rest = stripQueryHash(h.slice(originPrefix.length));
+        const slugPart = rest.trim();
+        return slugPart ? decodeURIComponent(slugPart) : null;
+      }
+
+      return null;
+    };
+
+    const fetchPreview = async (targetSlug: string) => {
+      const key = targetSlug.trim();
+      if (!key.length) return;
+
+      const cached = previewCacheRef.current.get(key);
+      if (cached) {
+        setLinkPreviewData({ slug: key, title: cached.title, quote: cached.quote, status: "ready" });
+        return;
+      }
+
+      setLinkPreviewData((prev) => ({ slug: key, title: prev?.title || key, quote: null, status: "loading" }));
+      try {
+        const row = await fetchWikiBySlug(key);
+        if (!row) {
+          setLinkPreviewData({ slug: key, title: key, quote: null, status: "error" });
+          return;
+        }
+
+        const html = normalizeWikiContentToHtml(row.content ?? "");
+        let quote: string | null = null;
+        try {
+          const parser = new DOMParser();
+          const doc = parser.parseFromString(html, "text/html");
+          const bq = doc.body.querySelector("blockquote");
+          const txt = String(bq?.textContent || "").trim();
+          quote = txt.length ? txt : null;
+        } catch {
+          quote = null;
+        }
+
+        const title = String(row.title || "").trim() || key;
+        previewCacheRef.current.set(key, { title, quote });
+        setLinkPreviewData({ slug: key, title, quote, status: "ready" });
+      } catch {
+        setLinkPreviewData({ slug: key, title: key, quote: null, status: "error" });
+      }
+    };
+
+    const showForAnchor = (a: HTMLAnchorElement) => {
+      const href = String(a.getAttribute("href") || "").trim();
+      const targetSlug = resolveInternalWikiSlug(href);
+      if (!targetSlug) return;
+
+      // Avoid previews on touch devices.
+      if (window.matchMedia && window.matchMedia("(hover: none)").matches) return;
+
+      const rect = a.getBoundingClientRect();
+      const width = 420;
+      const height = 320;
+      const margin = 12;
+
+      const preferredLeft = rect.right + margin;
+      const maxLeft = Math.max(margin, window.innerWidth - width - margin);
+      const left = Math.min(preferredLeft, maxLeft);
+
+      const preferredTop = rect.top;
+      const maxTop = Math.max(margin, window.innerHeight - height - margin);
+      const top = Math.max(margin, Math.min(preferredTop, maxTop));
+
+      clearHideTimer();
+      setLinkPreview({ slug: targetSlug, top, left, width, height, visible: true });
+      void fetchPreview(targetSlug);
+    };
+
+    const onMouseOver = (evt: MouseEvent) => {
+      const target = evt.target as HTMLElement | null;
+      const a = target?.closest?.("a") as HTMLAnchorElement | null;
+      if (!a) return;
+      showForAnchor(a);
+    };
+
+    const onMouseOut = (evt: MouseEvent) => {
+      const target = evt.target as HTMLElement | null;
+      const related = evt.relatedTarget as HTMLElement | null;
+      const fromA = target?.closest?.("a");
+      if (!fromA) return;
+      if (related && related.closest?.(".uhm-wiki-link-preview")) return;
+      hideSoon();
+    };
+
+    const onKeyDown = (evt: KeyboardEvent) => {
+      if (evt.key === "Escape") {
+        clearHideTimer();
+        setLinkPreview((prev) => (prev ? { ...prev, visible: false } : prev));
+      }
+    };
+
+    const onScroll = () => {
+      setLinkPreview((prev) => (prev ? { ...prev, visible: false } : prev));
+    };
+
+    root.addEventListener("mouseover", onMouseOver);
+    root.addEventListener("mouseout", onMouseOut);
+    window.addEventListener("keydown", onKeyDown);
+    window.addEventListener("scroll", onScroll, { passive: true });
+
+    return () => {
+      root.removeEventListener("mouseover", onMouseOver);
+      root.removeEventListener("mouseout", onMouseOut);
+      window.removeEventListener("keydown", onKeyDown);
+      window.removeEventListener("scroll", onScroll);
+      clearHideTimer();
+    };
+  }, [renderHtml]);
+
   return (
     <div className="min-h-screen bg-white text-gray-900 dark:bg-gray-950 dark:text-gray-100">
       <div className="mx-auto max-w-6xl px-4 py-6">
@@ -360,6 +528,60 @@ export default function WikiBySlugClient({ slug }: { slug: string }) {
         )}
       </div>
 
+      {linkPreview && linkPreview.visible ? (
+        <div
+          className="uhm-wiki-link-preview fixed z-[9999]"
+          style={{
+            top: linkPreview.top,
+            left: linkPreview.left,
+            width: linkPreview.width,
+            height: linkPreview.height,
+          }}
+          onMouseEnter={() => {
+            if (hidePreviewTimerRef.current != null) {
+              window.clearTimeout(hidePreviewTimerRef.current);
+              hidePreviewTimerRef.current = null;
+            }
+          }}
+          onMouseLeave={() => {
+            setLinkPreview((prev) => (prev ? { ...prev, visible: false } : prev));
+          }}
+        >
+          <div className="h-full w-full overflow-hidden rounded-xl border border-gray-200 dark:border-gray-800 bg-white dark:bg-gray-900 shadow-lg">
+            <div className="h-full w-full p-3 grid grid-rows-[auto_1fr] gap-2">
+              <div className="min-w-0">
+                <div className="text-[11px] text-gray-500 dark:text-gray-400 break-all">
+                  /wiki/{linkPreview.slug}
+                </div>
+                <div className="mt-0.5 text-sm font-semibold text-gray-900 dark:text-gray-100 truncate">
+                  {linkPreviewData?.slug === linkPreview.slug
+                    ? linkPreviewData.status === "loading"
+                      ? "Loading..."
+                      : linkPreviewData.status === "error"
+                        ? "Not found"
+                        : linkPreviewData.title
+                    : "Loading..."}
+                </div>
+              </div>
+
+              <div className="min-h-0 overflow-auto">
+                {linkPreviewData?.slug === linkPreview.slug && linkPreviewData.status === "ready" ? (
+                  linkPreviewData.quote ? (
+                      <div className="text-xs text-gray-500 dark:text-gray-400 whitespace-pre-wrap break-words">
+                        {linkPreviewData.quote}
+                      </div>
+                  ) : (
+                    <div className="text-xs text-gray-500 dark:text-gray-400">No resume.</div>
+                  )
+                ) : (
+                  <div className="text-xs text-gray-500 dark:text-gray-400">Loading preview...</div>
+                )}
+              </div>
+            </div>
+          </div>
+        </div>
+      ) : null}
+
       <style jsx global>{`
         /* Quill view container tweaks: allow page-level scrolling instead of inner scroll. */
         .uhm-wiki-view.ql-editor {
@@ -442,10 +664,10 @@ export default function WikiBySlugClient({ slug }: { slug: string }) {
           text-decoration-thickness: from-font;
           text-underline-offset: 2px;
         }
-        .uhm-wiki-view.ql-editor a[href]:not([href=""]) {
+        .uhm-wiki-view.ql-editor a[href]:not([href=""]):not([href="__missing__"]) {
           color: #2563eb;
         }
-        :is(.dark *) .uhm-wiki-view.ql-editor a[href]:not([href=""]) {
+        :is(.dark *) .uhm-wiki-view.ql-editor a[href]:not([href=""]):not([href="__missing__"]) {
           color: #60a5fa;
         }
         .uhm-wiki-view.ql-editor a[href="__missing__"] {
diff --git a/src/uhm/components/WikiSidebarPanel.tsx b/src/uhm/components/WikiSidebarPanel.tsx
index 4b45f73..e08528b 100644
--- a/src/uhm/components/WikiSidebarPanel.tsx
+++ b/src/uhm/components/WikiSidebarPanel.tsx
@@ -303,11 +303,7 @@ export default function WikiSidebarPanel({ projectId, wikis, setWikis, autoOpen,
           setWikiSaveError("Noi dung file khong phai HTML hop le.");
           return;
         }
-
-        // Quill drops <a> tags that do not have a valid href.
-        // Preserve the intent by inserting a placeholder href.
-        const normalized = ensureAnchorsHaveHref(raw);
-        setWikiDocHtml(normalized);
+        setWikiDocHtml(raw);
         setWikiSaveError(null);
       } catch (err) {
         const msg = err instanceof Error ? err.message : "Khong import duoc file.";
@@ -462,6 +458,33 @@ export default function WikiSidebarPanel({ projectId, wikis, setWikis, autoOpen,
     closeWikiLinkModal();
   }, [closeWikiLinkModal]);
 
+  const applyMissingWikiLink = useCallback(() => {
+    const intent = wikiLinkIntentRef.current;
+    const quill = intent?.quill;
+    if (!quill) return;
+
+    const href = "__missing__";
+    const range = intent?.range ?? quill.getSelection?.() ?? null;
+    if (!range) {
+      setWikiLinkError("Khong lay duoc vi tri selection trong editor.");
+      return;
+    }
+
+    quill.setSelection?.(range.index, range.length, "silent");
+
+    if (range.length > 0) {
+      quill.formatText?.(range.index, range.length, "link", href, "user");
+      closeWikiLinkModal();
+      return;
+    }
+
+    // No selection: insert query text (best effort) and mark it as a missing link.
+    const label = wikiLinkQuery.trim().slice(0, 120) || "link";
+    quill.insertText?.(range.index, label, { link: href }, "user");
+    quill.setSelection?.(range.index + label.length, 0, "silent");
+    closeWikiLinkModal();
+  }, [closeWikiLinkModal, wikiLinkQuery]);
+
   const removeWikiLink = useCallback(() => {
     const intent = wikiLinkIntentRef.current;
     const quill = intent?.quill;
@@ -784,32 +807,8 @@ export default function WikiSidebarPanel({ projectId, wikis, setWikis, autoOpen,
           </div>
 
           <div className="mt-5 grid grid-cols-1 lg:grid-cols-4 gap-6 flex-1 min-h-0 overflow-auto">
-            <div className="lg:col-span-1">
-              <div className="text-xs font-semibold text-gray-700 dark:text-gray-200 mb-2">Wikis</div>
-              <div className="flex flex-col gap-2">
-                {wikis.map((w) => (
-                  <button
-                    key={w.id}
-                    type="button"
-                    onClick={() => setActiveId(w.id)}
-                    className={`text-left rounded-xl border px-3 py-2 text-sm transition ${
-                      w.id === activeId
-                        ? "border-brand-500 bg-brand-50 dark:bg-brand-500/10"
-                        : "border-gray-200 dark:border-gray-800 bg-white dark:bg-[#0d1117]"
-                    }`}
-                    title={w.title}
-                  >
-                    <div className="font-medium truncate">{w.title}</div>
-                    <div className="text-[11px] text-gray-500 dark:text-gray-400 truncate">{w.id}</div>
-                  </button>
-                ))}
-                <Button size="sm" variant="outline" onClick={openEditor}>
-                  + New wiki
-                </Button>
-              </div>
-            </div>
 
-            <div className="lg:col-span-3">
+            <div className="lg:col-span-5">
               <div className="grid grid-cols-1 gap-3">
                 <div>
                   <Label>Title</Label>
@@ -863,6 +862,19 @@ export default function WikiSidebarPanel({ projectId, wikis, setWikis, autoOpen,
         .uhm-wiki-quill .ql-editor p {
           color: #000 !important;
         }
+        /* Differentiate missing links vs real links inside the editor. */
+        .uhm-wiki-quill .ql-editor a {
+          text-decoration: underline;
+          text-underline-offset: 2px;
+        }
+        .uhm-wiki-quill .ql-editor a[href="__missing__"],
+        .uhm-wiki-quill .ql-editor a:not([href]),
+        .uhm-wiki-quill .ql-editor a[href=""] {
+          color: #dc2626 !important;
+        }
+        .uhm-wiki-quill .ql-editor a[href]:not([href=""]):not([href="__missing__"]) {
+          color: #2563eb !important;
+        }
       `}</style>
 
       <Modal
@@ -946,6 +958,9 @@ export default function WikiSidebarPanel({ projectId, wikis, setWikis, autoOpen,
           </div>
 
           <div className="flex items-center justify-end gap-2">
+            <Button size="sm" variant="outline" onClick={applyMissingWikiLink}>
+              Empty link
+            </Button>
             {wikiLinkIntentRef.current?.existingHref ? (
               <Button size="sm" variant="outline" onClick={removeWikiLink}>
                 Remove link
@@ -987,6 +1002,7 @@ function CloseIcon() {
 
 const QUILL_TOOLBAR = [
   [{ header: [1, 2, 3, false] }],
+  [{ align: [] }, { align: "center" }, { align: "right" }],
   ["bold", "italic", "underline", "strike"],
   [{ list: "ordered" }, { list: "bullet" }],
   ["blockquote", "code-block"],
@@ -1087,25 +1103,3 @@ function downloadTextFile(filename: string, contents: string, mime: string): voi
   a.remove();
   window.setTimeout(() => URL.revokeObjectURL(url), 0);
 }
-
-function ensureAnchorsHaveHref(html: string): string {
-  const raw = String(html || "").trim();
-  if (!raw.length) return "";
-  if (typeof window === "undefined") return raw;
-
-  try {
-    const parser = new DOMParser();
-    const doc = parser.parseFromString(raw, "text/html");
-    const anchors = Array.from(doc.querySelectorAll("a"));
-    for (const a of anchors) {
-      const href = a.getAttribute("href");
-      if (href == null || String(href).trim() === "") {
-        // Placeholder: the viewer will render this as "missing" (red) and will not rewrite it.
-        a.setAttribute("href", "__missing__");
-      }
-    }
-    return doc.body.innerHTML;
-  } catch {
-    return raw;
-  }
-}