diff --git a/backend/social/chat/consumers.py b/backend/social/chat/consumers.py
index 04c27be..077faf0 100644
--- a/backend/social/chat/consumers.py
+++ b/backend/social/chat/consumers.py
@@ -120,9 +120,11 @@ class ChatConsumer(AsyncWebsocketConsumer):
             "type": "new_chat_message",
             "message_id": event["message_id"],
             "message": event["message"],
-            "sender_id": event["sender_id"],
+            "sender_id": event.get("sender_id"),
             "sender": event["sender"],
-            "sender_avatar": event["sender_avatar"],
+            "sender_avatar": event.get("sender_avatar"),
+            "reply_to_id": event.get("reply_to_id"),
+            "media_files": event.get("media_files", []),
         }))
 
     async def reply_chat_message(self, event):
diff --git a/backend/social/chat/serializers.py b/backend/social/chat/serializers.py
index 81cec0d..7349059 100644
--- a/backend/social/chat/serializers.py
+++ b/backend/social/chat/serializers.py
@@ -4,6 +4,7 @@ from drf_spectacular.utils import extend_schema_field
 from .models import Chat, ChatReadStatus, Message, MessageFile, MessageHistory, MessageReaction
 
 
+
 class MessageSenderSerializer(serializers.ModelSerializer):
     avatar = serializers.SerializerMethodField()
 
@@ -51,10 +52,42 @@ class ReplyToSerializer(serializers.ModelSerializer):
 
 class MessageSerializer(serializers.ModelSerializer):
     sender = MessageSenderSerializer(read_only=True)
-    reply_to = ReplyToSerializer(read_only=True)
+    # reply_to is a SerializerMethodField so we can bypass ActiveManager and
+    # still surface a tombstone when the original message is soft-deleted.
+    reply_to = serializers.SerializerMethodField()
     media_files = MessageFileSerializer(many=True, read_only=True)
     reactions = MessageReactionSerializer(many=True, read_only=True)
 
+    @extend_schema_field(ReplyToSerializer)
+    def get_reply_to(self, obj):
+        """
+        Fetch the reply-to message via all_objects so soft-deleted originals
+        are still accessible. Returns content=None when the message is deleted,
+        which the frontend renders as a '(zpráva smazána)' tombstone.
+        """
+        reply_to_id = obj.reply_to_id
+        if not reply_to_id:
+            return None
+        try:
+            msg = Message.all_objects.select_related('sender').get(pk=reply_to_id)
+        except Message.DoesNotExist:
+            return None
+
+        sender_data = None
+        if msg.sender:
+            from django.conf import settings
+            avatar = (settings.MEDIA_URL + msg.sender.avatar.name) if msg.sender.avatar else None
+            sender_data = {'id': msg.sender.id, 'username': msg.sender.username, 'avatar': avatar}
+        else:
+            sender_data = {'id': 0, 'username': '…', 'avatar': None}
+
+        return {
+            'id': msg.id,
+            # content=None signals the frontend to show the deleted tombstone
+            'content': None if msg.is_deleted else msg.content,
+            'sender': sender_data,
+        }
+
     class Meta:
         model = Message
         fields = [
diff --git a/backend/social/chat/views.py b/backend/social/chat/views.py
index 64fab61..0128422 100644
--- a/backend/social/chat/views.py
+++ b/backend/social/chat/views.py
@@ -241,12 +241,26 @@ class MessageViewSet(viewsets.ModelViewSet):
                 mt = 'FILE'
             MessageFile.objects.create(message=message, file=f, media_type=mt)
 
+        from django.conf import settings
+        avatar_url = (settings.MEDIA_URL + request.user.avatar.name) if request.user.avatar else None
+        media_files_data = [
+            {
+                'id': f.id,
+                'file': settings.MEDIA_URL + f.file.name if f.file else '',
+                'media_type': f.media_type,
+                'uploaded_at': f.uploaded_at.isoformat(),
+            }
+            for f in message.media_files.all()
+        ]
         _broadcast(chat.id, {
             'type': 'chat.message',
             'message_id': message.id,
             'message': message.content,
+            'sender_id': request.user.id,
             'sender': request.user.username,
-            'has_files': message.media_files.exists(),
+            'sender_avatar': avatar_url,
+            'reply_to_id': message.reply_to_id,
+            'media_files': media_files_data,
         })
 
         return Response(
diff --git a/frontend/src/api/social/chatSend.ts b/frontend/src/api/social/chatSend.ts
new file mode 100644
index 0000000..330ea31
--- /dev/null
+++ b/frontend/src/api/social/chatSend.ts
@@ -0,0 +1,34 @@
+import { privateMutator } from "@/api/privateClient";
+import type { Message } from "@/api/generated/private/models/message";
+
+export interface SendMessageParams {
+  chatId: number;
+  content?: string;
+  replyToId?: number;
+  files?: File[];
+}
+
+/**
+ * Sends a chat message via HTTP multipart POST.
+ * Use this whenever files are attached; text-only messages can go through WS.
+ */
+export async function sendChatMessage({
+  chatId,
+  content,
+  replyToId,
+  files,
+}: SendMessageParams): Promise<Message> {
+  const form = new FormData();
+  form.append("chat", String(chatId));
+  if (content) form.append("content", content);
+  if (replyToId != null) form.append("reply_to", String(replyToId));
+  for (const file of files ?? []) {
+    form.append("files", file);
+  }
+  // privateMutator deletes Content-Type for FormData so Axios sets the multipart boundary
+  return privateMutator<Message>({
+    url: "/api/social/messages/send/",
+    method: "POST",
+    data: form,
+  });
+}
diff --git a/frontend/src/components/social/chat/ChatMediaGallery.tsx b/frontend/src/components/social/chat/ChatMediaGallery.tsx
new file mode 100644
index 0000000..86a5e0f
--- /dev/null
+++ b/frontend/src/components/social/chat/ChatMediaGallery.tsx
@@ -0,0 +1,240 @@
+import { useState, useEffect, useCallback } from "react";
+import { createPortal } from "react-dom";
+import { FiX, FiChevronLeft, FiChevronRight, FiFile, FiDownload } from "react-icons/fi";
+import type { MessageFile } from "@/api/generated/private/models/messageFile";
+import { mediaUrl } from "@/utils/mediaUrl";
+
+interface Props {
+  files: readonly MessageFile[];
+}
+
+export default function ChatMediaGallery({ files }: Props) {
+  const [lightboxIndex, setLightboxIndex] = useState<number | null>(null);
+  const visible = files.slice(0, 4);
+  const overflow = files.length - visible.length;
+  const isOpen = lightboxIndex !== null;
+
+  const prev = useCallback(
+    () => setLightboxIndex((i) => (i !== null ? (i - 1 + files.length) % files.length : null)),
+    [files.length],
+  );
+  const next = useCallback(
+    () => setLightboxIndex((i) => (i !== null ? (i + 1) % files.length : null)),
+    [files.length],
+  );
+  const close = useCallback(() => setLightboxIndex(null), []);
+
+  useEffect(() => {
+    if (!isOpen) return;
+    function onKey(e: KeyboardEvent) {
+      if (e.key === "Escape") close();
+      if (e.key === "ArrowLeft") prev();
+      if (e.key === "ArrowRight") next();
+    }
+    window.addEventListener("keydown", onKey);
+    return () => window.removeEventListener("keydown", onKey);
+  }, [isOpen, close, prev, next]);
+
+  if (!files?.length) return null;
+
+  const layoutClass = visible.length === 1 ? "grid-cols-1" : "grid-cols-2";
+
+  return (
+    <>
+      <div className={`mt-2 grid ${layoutClass} gap-px overflow-hidden rounded-xl bg-brand-lines/20`}>
+        {visible.map((file, i) => (
+          <ChatMediaItem
+            key={file.id}
+            file={file}
+            overflowCount={i === 3 && overflow > 0 ? overflow : 0}
+            onOpen={() => setLightboxIndex(i)}
+          />
+        ))}
+      </div>
+
+      {isOpen &&
+        createPortal(
+          <div
+            className="fixed inset-0 z-50 flex items-center justify-center bg-black/80 backdrop-blur-sm"
+            onClick={close}
+          >
+            <button
+              type="button"
+              onClick={close}
+              className="absolute right-4 top-4 flex h-9 w-9 items-center justify-center rounded-full bg-white/10 text-white hover:bg-white/20 transition-colors"
+            >
+              <FiX size={20} />
+            </button>
+
+            {files.length > 1 && (
+              <button
+                type="button"
+                onClick={(e) => { e.stopPropagation(); prev(); }}
+                className="absolute left-4 flex h-10 w-10 items-center justify-center rounded-full bg-white/10 text-white hover:bg-white/20 transition-colors"
+              >
+                <FiChevronLeft size={24} />
+              </button>
+            )}
+
+            <ChatLightboxContent file={files[lightboxIndex!]} />
+
+            {files.length > 1 && (
+              <button
+                type="button"
+                onClick={(e) => { e.stopPropagation(); next(); }}
+                className="absolute right-4 flex h-10 w-10 items-center justify-center rounded-full bg-white/10 text-white hover:bg-white/20 transition-colors"
+              >
+                <FiChevronRight size={24} />
+              </button>
+            )}
+
+            {files.length > 1 && (
+              <div
+                className="absolute bottom-5 flex items-center gap-2"
+                onClick={(e) => e.stopPropagation()}
+              >
+                {files.map((_, i) => (
+                  <button
+                    key={i}
+                    type="button"
+                    onClick={() => setLightboxIndex(i)}
+                    className={[
+                      "h-2 rounded-full transition-all duration-200",
+                      i === lightboxIndex ? "w-5 bg-white" : "w-2 bg-white/40 hover:bg-white/70",
+                    ].join(" ")}
+                  />
+                ))}
+              </div>
+            )}
+          </div>,
+          document.body,
+        )}
+    </>
+  );
+}
+
+function ChatLightboxContent({ file }: { file: MessageFile }) {
+  const url = mediaUrl(file.file) ?? "";
+  const type = file.media_type ?? "FILE";
+
+  if (type === "VIDEO") {
+    return (
+      <video
+        src={url}
+        controls
+        className="max-h-[90vh] max-w-[90vw] rounded-xl shadow-2xl"
+        onClick={(e) => e.stopPropagation()}
+      />
+    );
+  }
+  if (type === "IMAGE") {
+    return (
+      <img
+        src={url}
+        alt=""
+        className="max-h-[90vh] max-w-[90vw] rounded-xl object-contain shadow-2xl select-none"
+        onClick={(e) => e.stopPropagation()}
+        draggable={false}
+      />
+    );
+  }
+  const filename = url.split("/").pop() ?? "soubor";
+  return (
+    <a
+      href={url}
+      download
+      target="_blank"
+      rel="noreferrer"
+      onClick={(e) => e.stopPropagation()}
+      className="flex flex-col items-center gap-4 rounded-2xl border border-white/20 bg-white/10 px-10 py-8 text-white hover:bg-white/20 transition-colors"
+    >
+      <FiFile size={48} />
+      <span className="max-w-xs truncate text-sm">{filename}</span>
+      <FiDownload size={20} className="opacity-70" />
+    </a>
+  );
+}
+
+function ChatMediaItem({
+  file,
+  onOpen,
+  overflowCount = 0,
+}: {
+  file: MessageFile;
+  onOpen: () => void;
+  overflowCount?: number;
+}) {
+  const url = mediaUrl(file.file) ?? "";
+  const type = file.media_type ?? "FILE";
+
+  const overlay =
+    overflowCount > 0 ? (
+      <div
+        className="absolute inset-0 flex items-center justify-center bg-black/55 cursor-pointer"
+        onClick={(e) => { e.stopPropagation(); onOpen(); }}
+      >
+        <span className="text-2xl font-semibold text-white">+{overflowCount}</span>
+      </div>
+    ) : null;
+
+  if (type === "VIDEO") {
+    return (
+      <div
+        className="relative aspect-square w-full max-w-[200px] bg-black cursor-pointer"
+        onClick={(e) => { e.stopPropagation(); onOpen(); }}
+      >
+        <video
+          src={url}
+          muted
+          playsInline
+          preload="metadata"
+          className="h-full w-full object-cover pointer-events-none"
+        />
+        <div className="absolute inset-0 flex items-center justify-center bg-black/20">
+          <div className="flex h-8 w-8 items-center justify-center rounded-full bg-white/20">
+            <svg viewBox="0 0 24 24" fill="white" className="h-4 w-4 translate-x-0.5">
+              <path d="M8 5v14l11-7z" />
+            </svg>
+          </div>
+        </div>
+        {overlay}
+      </div>
+    );
+  }
+
+  if (type === "IMAGE") {
+    return (
+      <div className="relative aspect-square w-full max-w-[200px] bg-brand-bg/60">
+        <img
+          src={url}
+          alt=""
+          className="h-full w-full cursor-zoom-in object-cover transition-opacity hover:opacity-90"
+          loading="lazy"
+          onClick={(e) => { e.stopPropagation(); onOpen(); }}
+        />
+        {overlay}
+      </div>
+    );
+  }
+
+  const filename = url.split("/").pop() ?? "soubor";
+  return (
+    <div className="relative p-1">
+      <a
+        href={url}
+        download
+        target="_blank"
+        rel="noreferrer"
+        onClick={(e) => e.stopPropagation()}
+        className="flex items-center gap-2 rounded-lg border border-brand-lines/20 bg-brand-bgLight/30 px-2 py-1.5 hover:bg-brand-lines/10 transition-colors"
+      >
+        <FiFile size={18} className="shrink-0 text-brand-text/40" />
+        <span className="max-w-[140px] truncate text-[11px] text-brand-text/70 leading-tight">
+          {filename}
+        </span>
+        <FiDownload size={12} className="shrink-0 text-brand-text/30" />
+      </a>
+      {overlay}
+    </div>
+  );
+}
diff --git a/frontend/src/components/social/chat/Message.tsx b/frontend/src/components/social/chat/Message.tsx
index 85f91f5..c0e22e2 100644
--- a/frontend/src/components/social/chat/Message.tsx
+++ b/frontend/src/components/social/chat/Message.tsx
@@ -2,6 +2,7 @@ import { useTranslation } from "react-i18next";
 import { FiTrash2, FiCornerUpLeft, FiSmile } from "react-icons/fi";
 import type { Message as MessageModel } from "@/api/generated/private/models/message";
 import type { Chat } from "@/api/generated/private/models/chat";
+import ChatMediaGallery from "@/components/social/chat/ChatMediaGallery";
 import Avatar from "@/components/ui/Avatar";
 import IconButton from "@/components/ui/IconButton";
 import { useAuth } from "@/hooks/useAuth";
@@ -14,9 +15,13 @@ interface Props {
   chat: Chat | null;
   onReply?: (message: MessageModel) => void;
   onReact?: (message: MessageModel, emoji: string) => void;
+  /** Triggers the flash-highlight animation on this message. */
+  highlighted?: boolean;
+  /** Called when the user clicks the reply preview to jump to the original. */
+  onScrollToMessage?: (messageId: number) => void;
 }
 
-export default function Message({ message, chat, onReply, onReact }: Props) {
+export default function Message({ message, chat, onReply, onReact, highlighted, onScrollToMessage }: Props) {
   const { t } = useTranslation("social");
   const { user } = useAuth();
   const sender = message.sender as { id: number; username: string; avatar: string | null } | null;
@@ -30,58 +35,122 @@ export default function Message({ message, chat, onReply, onReact }: Props) {
 
   const canDelete = canDeleteMessage(user, message, chat);
 
+  // Compute reply state once, outside JSX.
+  const replyTo = message.reply_to;
+  const replyDeleted = replyTo != null && replyTo.content == null;
+  function handleJump() {
+    if (replyTo && !replyDeleted) onScrollToMessage?.(replyTo.id);
+  }
+
+  const hasMedia = (message.media_files?.length ?? 0) > 0;
+  const hasText  = !!message.content;
+
+  /**
+   * Grid columns:
+   *   non-own  →  [28px avatar] [bubble col, ≤70%] [actions auto]
+   *   own      →  [actions auto] [bubble col, ≤70%] [28px avatar]
+   *
+   * Rows are always:  1=reply  2=bubble  3=timestamp  4=reactions
+   * Avatar sits in col 1/3, row-start-2, self-center → locked to bubble height.
+   */
   return (
-    <div className={`group flex items-end gap-2 px-4 py-1.5 ${isOwn ? "flex-row-reverse" : ""}`}>
-      <Avatar name={sender?.username} src={sender?.avatar} size={28} />
-      <div className={`flex max-w-[70%] flex-col gap-1 ${isOwn ? "items-end" : "items-start"}`}>
-        {message.reply_to && (
-          <div
-            className={[
-              "rounded-xl border-l-2 px-2.5 py-1.5 text-xs",
-              isOwn
-                ? "border-white/40 bg-brand-lines/20 text-brand-text/60"
-                : "border-brand-accent/50 bg-brand-lines/20 text-brand-text/60",
-            ].join(" ")}
-          >
-            <span className="font-semibold text-brand-accent">
-              {message.reply_to.sender?.username ?? "…"}
-            </span>
-            <span className="ml-1">
-              {(message.reply_to.content ?? "").slice(0, 80) || "…"}
-            </span>
-          </div>
-        )}
+    <div
+      id={`msg-${message.id}`}
+      className={[
+        "group grid gap-x-2 gap-y-0 px-4 py-1.5",
+        isOwn
+          ? "grid-cols-[auto_minmax(0,70%)_28px]"
+          : "grid-cols-[28px_minmax(0,70%)_auto]",
+      ].join(" ")}
+    >
+      {/* Row 1 – reply preview + ↩ icon + sender username */}
+      {replyTo && (
         <div
           className={[
-            "rounded-2xl glass px-3 py-2 text-sm wrap-break-word whitespace-pre-wrap",
-            isOwn
-              ? "bg-brand-accent text-brand-bg rounded-br-sm"
-              : "bg-brand-bgLight/70 text-brand-text rounded-bl-sm",
+            "col-start-2 row-start-1 flex items-center gap-2",
+            "opacity-50 transition-opacity hover:opacity-90",
+            isOwn ? "justify-end" : "",
           ].join(" ")}
         >
-          {message.content}
-        </div>
-        <div className="mt-0.5 flex items-center gap-2 text-[11px] text-brand-text/50">
-          <time dateTime={String(message.created_at)}>
-            {formatRelative(message.created_at)}
-          </time>
-          {message.is_edited && <span>· {t("chat.room.edited")}</span>}
-        </div>
-        {message.reactions?.length > 0 && (
-          <div className="mt-1 flex flex-wrap gap-1">
-            {message.reactions.map((r) => (
-              <span
-                key={r.id}
-                className="rounded-full bg-brand-bgLight/60 px-2 py-0.5 text-xs"
-              >
-                {r.emoji}
+          <div
+            role={replyDeleted ? undefined : "button"}
+            tabIndex={replyDeleted ? undefined : 0}
+            onClick={replyDeleted ? undefined : handleJump}
+            onKeyDown={replyDeleted ? undefined : (e) => e.key === "Enter" && handleJump()}
+            className={[
+              "w-fit select-none rounded-lg border-l-2 px-3 py-1.5 text-xs",
+              replyDeleted ? "cursor-default" : "cursor-pointer",
+              isOwn
+                ? "border-white/30 bg-brand-lines/10 text-brand-text/50"
+                : "border-brand-accent/40 bg-brand-lines/10 text-brand-text/50",
+            ].join(" ")}
+          >
+            {replyDeleted ? (
+              <span className="whitespace-nowrap italic text-brand-text/40">{t("chat.room.deletedMessage")}</span>
+            ) : (
+              <span>
+                <span className="font-bold text-brand-accent/80">
+                  @{replyTo.sender?.username ?? "…"}
+                </span>
+                <span className="ml-1 italic text-brand-text/60">
+                  {(replyTo.content ?? "").slice(0, 80) || "…"}
+                </span>
               </span>
-            ))}
+            )}
+          </div>
+
+          {/* ↩ icon */}
+          <FiCornerUpLeft size={18} className="mr-3 shrink-0 text-brand-accent/50" />
+
+          {/* Sender username */}
+          {!isOwn && sender?.username && (
+            <span className="shrink-0 text-[11px] font-medium text-brand-accent/80">
+              {sender.username}
+            </span>
+          )}
+        </div>
+      )}
+
+      {/* Row 2 – avatar: pinned to top so it doesn't stretch to image height */}
+      <div className={`row-start-2 self-start mt-1 ${isOwn ? "col-start-3" : "col-start-1"}`}>
+        <Avatar name={sender?.username} src={sender?.avatar} size={28} />
+      </div>
+
+      {/* Row 2 – bubble
+           Text-only  → narrow w-fit bubble
+           Media-only → no bubble shell, gallery fills the column
+           Text+media → bubble for text (px-3 pt-2 pb-0), gallery bleeds to edge via -mx-3 */}
+      <div
+        className={[
+          "col-start-2 row-start-2 overflow-hidden rounded-2xl text-sm",
+          highlighted ? "msg-flash" : "",
+          !hasMedia ? "w-fit max-w-full wrap-break-word whitespace-pre-wrap" : "max-w-[min(70%,320px)]",
+          hasText ? "glass" : "",
+          hasText && !hasMedia ? "px-3 py-2" : "",
+          hasText &&  hasMedia ? "px-3 pt-2 pb-0" : "",
+          isOwn
+            ? `justify-self-end rounded-br-sm ${hasText ? "bg-brand-accent text-brand-bg" : ""}`
+            : `rounded-bl-sm ${hasText ? "bg-brand-bgLight/70 text-brand-text" : ""}`,
+        ].join(" ")}
+      >
+        {hasText && (
+          <p className="wrap-break-word whitespace-pre-wrap">{message.content}</p>
+        )}
+        {hasMedia && (
+          // -mx-3 cancels the px-3 padding so gallery is flush with the bubble edges
+          <div className={hasText ? "-mx-3 mt-2" : ""}>
+            <ChatMediaGallery files={message.media_files} />
           </div>
         )}
       </div>
 
-      <div className="flex items-center gap-1 opacity-0 transition-opacity group-hover:opacity-100">
+      {/* Row 2 – action buttons */}
+      <div
+        className={[
+          "row-start-2 flex items-center gap-1 self-center opacity-0 transition-opacity group-hover:opacity-100",
+          isOwn ? "col-start-1" : "col-start-3",
+        ].join(" ")}
+      >
         <IconButton
           icon={<FiCornerUpLeft size={14} />}
           label={t("chat.actions.reply")}
@@ -100,6 +169,38 @@ export default function Message({ message, chat, onReply, onReact }: Props) {
           />
         )}
       </div>
+
+      {/* Row 3 – timestamp (bubble column) */}
+      <div
+        className={[
+          "col-start-2 row-start-3 mt-0.5 flex items-center gap-2 text-[11px] text-brand-text/50",
+          isOwn ? "justify-self-end" : "",
+        ].join(" ")}
+      >
+        <time dateTime={String(message.created_at)}>
+          {formatRelative(message.created_at)}
+        </time>
+        {message.is_edited && <span>· {t("chat.room.edited")}</span>}
+      </div>
+
+      {/* Row 4 – reactions (bubble column) */}
+      {message.reactions?.length > 0 && (
+        <div
+          className={[
+            "col-start-2 row-start-4 mt-1 flex flex-wrap gap-1",
+            isOwn ? "justify-self-end" : "",
+          ].join(" ")}
+        >
+          {message.reactions.map((r) => (
+            <span
+              key={r.id}
+              className="rounded-full bg-brand-bgLight/60 px-2 py-0.5 text-xs"
+            >
+              {r.emoji}
+            </span>
+          ))}
+        </div>
+      )}
     </div>
   );
 }
diff --git a/frontend/src/components/social/chat/MessageComposer.tsx b/frontend/src/components/social/chat/MessageComposer.tsx
index 01934b7..af57fc6 100644
--- a/frontend/src/components/social/chat/MessageComposer.tsx
+++ b/frontend/src/components/social/chat/MessageComposer.tsx
@@ -1,6 +1,6 @@
 import { useEffect, useRef, useState } from "react";
 import { useTranslation } from "react-i18next";
-import { FiSend, FiX } from "react-icons/fi";
+import { FiSend, FiX, FiPaperclip, FiFile } from "react-icons/fi";
 import type { Message } from "@/api/generated/private/models/message";
 import Button from "@/components/ui/Button";
 
@@ -8,7 +8,7 @@ interface Props {
   disabled?: boolean;
   replyTo?: Message | null;
   onCancelReply?: () => void;
-  onSend: (text: string, replyToId?: number) => boolean;
+  onSend: (text: string, replyToId?: number, files?: File[]) => boolean | Promise<boolean>;
   onTyping?: (isTyping: boolean) => void;
 }
 
@@ -21,6 +21,9 @@ export default function MessageComposer({
 }: Props) {
   const { t } = useTranslation("social");
   const [text, setText] = useState("");
+  const [files, setFiles] = useState<File[]>([]);
+  const [sending, setSending] = useState(false);
+  const fileInputRef = useRef<HTMLInputElement>(null);
   const typingTimerRef = useRef<number | null>(null);
   const isTypingRef = useRef(false);
 
@@ -31,6 +34,15 @@ export default function MessageComposer({
     };
   }, [onTyping]);
 
+  // Revoke object URLs on unmount / file change to avoid memory leaks
+  useEffect(() => {
+    return () => {
+      files.forEach((f) => {
+        if ((f as any)._previewUrl) URL.revokeObjectURL((f as any)._previewUrl);
+      });
+    };
+  }, [files]);
+
   function notifyTyping() {
     if (!isTypingRef.current) {
       isTypingRef.current = true;
@@ -43,67 +55,122 @@ export default function MessageComposer({
     }, 2500);
   }
 
-  function handleSubmit(e: React.FormEvent) {
+  function addFiles(incoming: FileList | null) {
+    if (!incoming) return;
+    const tagged = Array.from(incoming).map((f) => {
+      (f as any)._previewUrl = f.type.startsWith("image/") ? URL.createObjectURL(f) : null;
+      return f;
+    });
+    setFiles((prev) => [...prev, ...tagged].slice(0, 10)); // max 10 files
+  }
+
+  function removeFile(idx: number) {
+    setFiles((prev) => {
+      const next = [...prev];
+      const removed = next.splice(idx, 1)[0];
+      if ((removed as any)._previewUrl) URL.revokeObjectURL((removed as any)._previewUrl);
+      return next;
+    });
+  }
+
+  async function handleSubmit(e: React.FormEvent) {
     e.preventDefault();
     const trimmed = text.trim();
-    if (!trimmed) return;
-    const ok = onSend(trimmed, replyTo?.id);
-    if (ok) {
-      setText("");
-      if (isTypingRef.current) {
-        isTypingRef.current = false;
-        onTyping?.(false);
+    if (!trimmed && files.length === 0) return;
+    setSending(true);
+    try {
+      const ok = await onSend(trimmed || "", replyTo?.id, files.length > 0 ? files : undefined);
+      if (ok) {
+        setText("");
+        setFiles([]);
+        if (isTypingRef.current) {
+          isTypingRef.current = false;
+          onTyping?.(false);
+        }
+        onCancelReply?.();
       }
-      onCancelReply?.();
+    } finally {
+      setSending(false);
     }
   }
 
+  const canSend = !disabled && !sending && (text.trim().length > 0 || files.length > 0);
+
   return (
-    <form
-      onSubmit={handleSubmit}
-      className="border-t border-brand-lines/15 bg-brand-bg/60 px-4 py-3"
-    >
+    <form onSubmit={handleSubmit} className="border-t border-brand-lines/15 bg-brand-bg/60 px-4 py-3">
       {replyTo && (
         <div className="mb-2 flex items-center justify-between gap-2 rounded-xl border border-brand-lines/15 bg-brand-bgLight/40 px-3 py-1.5 text-xs text-brand-text/80">
           <span className="truncate">
-            {t("chat.composer.replyTo", {
-              snippet: (replyTo.content ?? "").slice(0, 60),
-            })}
+            {t("chat.composer.replyTo", { snippet: (replyTo.content ?? "").slice(0, 60) })}
           </span>
-          <button
-            type="button"
-            onClick={onCancelReply}
-            className="rounded-full p-1 hover:bg-brand-lines/10"
-            aria-label={t("chat.composer.cancelReply")}
-          >
+          <button type="button" onClick={onCancelReply} className="rounded-full p-1 hover:bg-brand-lines/10" aria-label={t("chat.composer.cancelReply")}>
             <FiX size={12} />
           </button>
         </div>
       )}
 
+      {/* File previews */}
+      {files.length > 0 && (
+        <div className="mb-2 flex flex-wrap gap-2">
+          {files.map((f, i) => (
+            <div key={i} className="group relative shrink-0">
+              {(f as any)._previewUrl ? (
+                <img
+                  src={(f as any)._previewUrl}
+                  alt={f.name}
+                  className="h-16 w-16 rounded-lg object-cover border border-brand-lines/20"
+                />
+              ) : (
+                <div className="flex h-16 w-16 flex-col items-center justify-center gap-1 rounded-lg border border-brand-lines/20 bg-brand-bgLight/40 px-1">
+                  <FiFile size={20} className="text-brand-text/50" />
+                  <span className="w-full truncate text-center text-[9px] text-brand-text/50 leading-tight">{f.name}</span>
+                </div>
+              )}
+              <button
+                type="button"
+                onClick={() => removeFile(i)}
+                className="absolute -right-1.5 -top-1.5 flex h-4 w-4 items-center justify-center rounded-full bg-brand-bg border border-brand-lines/20 text-brand-text/60 hover:text-brand-text opacity-0 group-hover:opacity-100 transition-opacity"
+              >
+                <FiX size={9} />
+              </button>
+            </div>
+          ))}
+        </div>
+      )}
+
       <div className="flex items-end gap-2">
+        {/* Hidden file input */}
+        <input
+          ref={fileInputRef}
+          type="file"
+          multiple
+          accept="image/*,video/*,.pdf,.doc,.docx,.zip,.txt"
+          className="hidden"
+          onChange={(e) => addFiles(e.target.files)}
+          onClick={(e) => { (e.target as HTMLInputElement).value = ""; }}
+        />
+        <button
+          type="button"
+          onClick={() => fileInputRef.current?.click()}
+          disabled={disabled || sending}
+          className="flex h-[42px] w-[42px] shrink-0 items-center justify-center rounded-xl border border-brand-lines/25 bg-brand-bgLight/40 text-brand-text/60 hover:text-brand-text hover:border-brand-accent transition-colors disabled:opacity-40"
+          aria-label={t("chat.composer.attach")}
+        >
+          <FiPaperclip size={16} />
+        </button>
+
         <textarea
           value={text}
-          onChange={(e) => {
-            setText(e.target.value);
-            notifyTyping();
-          }}
+          onChange={(e) => { setText(e.target.value); notifyTyping(); }}
           onKeyDown={(e) => {
-            if (e.key === "Enter" && !e.shiftKey) {
-              e.preventDefault();
-              handleSubmit(e);
-            }
+            if (e.key === "Enter" && !e.shiftKey) { e.preventDefault(); handleSubmit(e); }
           }}
-          disabled={disabled}
+          disabled={disabled || sending}
           rows={1}
           placeholder={t("chat.composer.placeholder")}
-          className="min-h-[42px] max-h-[160px] flex-1 resize-none rounded-xl border border-brand-lines/25 bg-brand-bgLight/40 px-3 py-2 text-sm text-brand-text placeholder:text-brand-text/40 focus:outline-none focus:border-brand-accent"
+          className="min-h-[42px] max-h-40 flex-1 resize-none rounded-xl border border-brand-lines/25 bg-brand-bgLight/40 px-3 py-2 text-sm text-brand-text placeholder:text-brand-text/40 focus:outline-none focus:border-brand-accent"
         />
-        <Button
-          type="submit"
-          disabled={disabled || !text.trim()}
-          leftIcon={<FiSend size={14} />}
-        >
+        <Button type="submit" disabled={!canSend} leftIcon={<FiSend size={14} />}>
           {t("common:send", { defaultValue: "Odeslat" })}
         </Button>
       </div>
diff --git a/frontend/src/hooks/useChatSocket.ts b/frontend/src/hooks/useChatSocket.ts
index 2879226..37d0de9 100644
--- a/frontend/src/hooks/useChatSocket.ts
+++ b/frontend/src/hooks/useChatSocket.ts
@@ -4,8 +4,8 @@ import { getChatSocketUrl } from "@/api/social/ws";
 export type ChatSocketStatus = "idle" | "connecting" | "open" | "closed" | "error";
 
 export type ChatSocketEvent =
-  | { type: "new_chat_message"; message_id: number; message: string; sender_id: number; sender: string; sender_avatar: string | null }
-  | { type: "new_reply_chat_message"; message_id: number; message: string; reply_to_id: number; sender_id: number; sender: string; sender_avatar: string | null }
+  | { type: "new_chat_message"; message_id: number; message: string; sender_id: number; sender: string; sender_avatar: string | null; reply_to_id?: number; media_files?: Array<{ id: number; file: string; media_type: string; uploaded_at: string }> }
+  | { type: "new_reply_chat_message"; message_id: number; message: string; reply_to_id: number; sender_id: number; sender: string; sender_avatar: string | null; media_files?: Array<{ id: number; file: string; media_type: string; uploaded_at: string }> }
   | { type: "edit_chat_message"; message_id: number; content: string; is_edited: boolean }
   | { type: "delete_chat_message"; message_id: number }
   | { type: "reaction"; message_id: number; emoji: string; user: string; action: "added" | "removed" | "switched" }
diff --git a/frontend/src/i18n/locales/cs/social.json b/frontend/src/i18n/locales/cs/social.json
index 034e3e4..97a0232 100644
--- a/frontend/src/i18n/locales/cs/social.json
+++ b/frontend/src/i18n/locales/cs/social.json
@@ -85,7 +85,10 @@
       "edited": "upraveno",
       "disconnected": "Spojení přerušeno, obnovuji...",
       "loadingHistory": "Načítání starších zpráv...",
-      "noMessages": "Žádné zprávy. Pošlete první!"
+      "noMessages": "Žádné zprávy. Pošlete první!",
+      "deletedMessage": "(zpráva smazána)",
+      "chatBeginning": "Toto je začátek konverzace",
+      "chatCreated": "Vytvořeno {{date}}"
     },
     "composer": {
       "placeholder": "Napište zprávu...",
diff --git a/frontend/src/index.css b/frontend/src/index.css
index bf88bc5..02085fd 100644
--- a/frontend/src/index.css
+++ b/frontend/src/index.css
@@ -105,6 +105,70 @@ h1, h2, h3 {
   width: 100%;
 }
 
+/* Chat message flash highlight when jumped to via reply */
+@keyframes msg-flash {
+  0%   {
+    background-color: transparent;
+    box-shadow: 0 0 0 0 transparent;
+  }
+  20%  {
+    background-color: color-mix(in hsl, var(--c-lines), transparent 88%);
+    box-shadow: 0 0 14px 4px color-mix(in hsl, var(--c-lines), transparent 65%);
+  }
+  70%  {
+    background-color: color-mix(in hsl, var(--c-lines), transparent 88%);
+    box-shadow: 0 0 14px 4px color-mix(in hsl, var(--c-lines), transparent 65%);
+  }
+  100% {
+    background-color: transparent;
+    box-shadow: 0 0 0 0 transparent;
+  }
+}
+.msg-flash {
+  animation: msg-flash 1.4s ease;
+}
+
+/* ── Global custom scrollbar ───────────────────────────────────────────────── */
+
+/* Firefox */
+* {
+  scrollbar-width: thin;
+  scrollbar-color: color-mix(in hsl, var(--c-lines), transparent 55%) transparent;
+}
+
+/* WebKit (Chrome, Edge, Safari) */
+::-webkit-scrollbar {
+  width: 5px;
+  height: 5px;
+}
+
+/* Track — fully transparent */
+::-webkit-scrollbar-track {
+  background: transparent;
+}
+
+/* Hide the up/down arrow buttons */
+::-webkit-scrollbar-button {
+  display: none;
+  height: 0;
+  width: 0;
+}
+
+/* Thumb */
+::-webkit-scrollbar-thumb {
+  background: color-mix(in hsl, var(--c-lines), transparent 55%);
+  border-radius: 99px;
+}
+
+::-webkit-scrollbar-thumb:hover {
+  background: color-mix(in hsl, var(--c-lines), transparent 30%);
+}
+
+/* Corner where horizontal + vertical scrollbars meet */
+::-webkit-scrollbar-corner {
+  background: transparent;
+}
+
 .nav-item:focus-visible {
   outline: 2px solid color-mix(in hsl, var(--c-other), transparent 20%);
   outline-offset: 2px;
diff --git a/frontend/src/layouts/social/Chat.tsx b/frontend/src/layouts/social/Chat.tsx
index 3154630..5950d1a 100644
--- a/frontend/src/layouts/social/Chat.tsx
+++ b/frontend/src/layouts/social/Chat.tsx
@@ -1,11 +1,34 @@
+import { useState } from "react";
 import { Outlet } from "react-router-dom";
+import { FiMenu, FiChevronsLeft } from "react-icons/fi";
 import ChatSidebar from "@/components/social/chat/ChatSidebar";
 
 export default function ChatLayout() {
+  const [open, setOpen] = useState(true);
+
   return (
-    <div className="grid h-[calc(100vh-0px)] grid-cols-[280px_1fr]">
-      <ChatSidebar />
-      <section className="flex h-full flex-col overflow-hidden">
+    <div
+      className={[
+        "grid h-screen transition-[grid-template-columns] duration-200",
+        open ? "grid-cols-[280px_1fr]" : "grid-cols-[0px_1fr]",
+      ].join(" ")}
+    >
+      {/* Sidebar — hidden via overflow+width collapse, not unmount (keeps scroll pos) */}
+      <div className="overflow-hidden">
+        <ChatSidebar />
+      </div>
+
+      <section className="relative flex h-full flex-col overflow-hidden">
+        {/* Sidebar toggle — sits at the top-left of the chat pane */}
+        <button
+          type="button"
+          onClick={() => setOpen((v) => !v)}
+          className="absolute left-3 top-3 z-20 flex h-7 w-7 items-center justify-center rounded-full bg-brand-bgLight/60 text-brand-text/60 hover:bg-brand-lines/20 hover:text-brand-text transition-colors"
+          aria-label={open ? "Hide sidebar" : "Show sidebar"}
+        >
+          {open ? <FiChevronsLeft size={15} /> : <FiMenu size={15} />}
+        </button>
+
         <Outlet />
       </section>
     </div>
diff --git a/frontend/src/layouts/social/SocialLayout.tsx b/frontend/src/layouts/social/SocialLayout.tsx
index 01a0713..30f64b9 100644
--- a/frontend/src/layouts/social/SocialLayout.tsx
+++ b/frontend/src/layouts/social/SocialLayout.tsx
@@ -93,20 +93,28 @@ export default function SocialLayout() {
           </div>
         </aside>
 
-        {/* Main column */}
-        <main className={`flex-1 border-x border-brand-lines/15 max-w-[640px] ${isChat ? "h-screen overflow-hidden" : "min-h-screen"}`}>
+        {/* Main column — expands to fill all available space in chat mode */}
+        <main
+          className={
+            isChat
+              ? "flex-1 h-screen overflow-hidden"
+              : "flex-1 border-x border-brand-lines/15 max-w-[640px] min-h-screen"
+          }
+        >
           <Outlet />
         </main>
 
-        {/* Right rail (placeholder; hidden on small screens) */}
-        <aside className="sticky top-0 hidden h-screen w-[300px] flex-shrink-0 py-6 lg:block">
-          <div className="glass rounded-2xl p-4 text-sm text-brand-text/70">
-            <div className="font-semibold text-brand-text mb-2">
-              {t("nav.hubs")}
+        {/* Right rail — hidden in chat (chat needs the space) */}
+        {!isChat && (
+          <aside className="sticky top-0 hidden h-screen w-[300px] shrink-0 py-6 lg:block">
+            <div className="glass rounded-2xl p-4 text-sm text-brand-text/70">
+              <div className="font-semibold text-brand-text mb-2">
+                {t("nav.hubs")}
+              </div>
+              <p className="text-xs">—</p>
             </div>
-            <p className="text-xs">—</p>
-          </div>
-        </aside>
+          </aside>
+        )}
       </div>
     </div>
   );
diff --git a/frontend/src/pages/social/chat/ChatRoomPage.tsx b/frontend/src/pages/social/chat/ChatRoomPage.tsx
index e269a8d..0247a91 100644
--- a/frontend/src/pages/social/chat/ChatRoomPage.tsx
+++ b/frontend/src/pages/social/chat/ChatRoomPage.tsx
@@ -10,6 +10,7 @@ import { useInfiniteMessages } from "@/hooks/useInfiniteMessages";
 import { useChatSocket, type ChatSocketEvent } from "@/hooks/useChatSocket";
 import { useIntersectionLoader } from "@/hooks/useIntersectionLoader";
 import { messagesQueryKey, type CursorPaginated } from "@/api/social/feed";
+import { sendChatMessage } from "@/api/social/chatSend";
 import Message from "@/components/social/chat/Message";
 import MessageComposer from "@/components/social/chat/MessageComposer";
 import ChatSettingsModal from "@/components/social/chat/ChatSettingsModal";
@@ -38,6 +39,53 @@ export default function ChatRoomPage() {
   const [settingsOpen, setSettingsOpen] = useState(false);
   const bottomRef = useRef<HTMLDivElement | null>(null);
 
+  // --- reply-jump logic ---
+  const [highlightedId, setHighlightedId] = useState<number | null>(null);
+  /** Message id we're waiting to appear in the DOM while fetching older pages. */
+  const [pendingScrollId, setPendingScrollId] = useState<number | null>(null);
+  /** IDs removed by a delete WS event — so we don't hunt for them in older pages. */
+  const deletedMessageIds = useRef(new Set<number>());
+
+  function flashMessage(id: number) {
+    setHighlightedId(id);
+    setTimeout(() => setHighlightedId(null), 1500);
+  }
+
+  function scrollToMessage(id: number) {
+    // Don't chase a message that was deleted during this session.
+    if (deletedMessageIds.current.has(id)) return;
+
+    const el = document.getElementById(`msg-${id}`);
+    if (el) {
+      el.scrollIntoView({ behavior: "smooth", block: "center" });
+      flashMessage(id);
+    } else if (hasNextPage) {
+      // Message not rendered yet — start fetching older pages until it appears.
+      setPendingScrollId(id);
+      void fetchNextPage();
+    }
+    // else: exhausted history, message not found — silently ignore.
+  }
+
+  // After every page load, try to resolve a pending scroll-to.
+  useEffect(() => {
+    if (!pendingScrollId) return;
+    const el = document.getElementById(`msg-${pendingScrollId}`);
+    if (el) {
+      el.scrollIntoView({ behavior: "smooth", block: "center" });
+      flashMessage(pendingScrollId);
+      setPendingScrollId(null);
+    } else if (!isFetchingNextPage) {
+      if (hasNextPage) {
+        void fetchNextPage();          // keep paging back until found
+      } else {
+        setPendingScrollId(null);      // exhausted history, give up
+      }
+    }
+  // Re-run whenever a new page arrives or fetching state changes.
+  // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [messages.length, isFetchingNextPage]);
+
   // Top sentinel triggers loading older messages (scroll-back).
   const topSentinelRef = useIntersectionLoader<HTMLDivElement>(
     () => {
@@ -68,6 +116,9 @@ export default function ChatRoomPage() {
 
   const removeMessage = useCallback(
     (messageId: number) => {
+      deletedMessageIds.current.add(messageId);
+      // Also cancel any pending scroll to this message.
+      setPendingScrollId((prev) => (prev === messageId ? null : prev));
       queryClient.setQueryData<{
         pages: CursorPaginated<MessageModel>[];
         pageParams: unknown[];
@@ -77,7 +128,15 @@ export default function ChatRoomPage() {
           ...old,
           pages: old.pages.map((p) => ({
             ...p,
-            results: p.results.filter((m) => m.id !== messageId),
+            results: p.results
+              // Remove the deleted message itself.
+              .filter((m) => m.id !== messageId)
+              // Tombstone reply_to.content for any message quoting the deleted one.
+              .map((m) =>
+                m.reply_to?.id === messageId
+                  ? { ...m, reply_to: { ...m.reply_to, content: undefined } }
+                  : m,
+              ),
           })),
         };
       });
@@ -108,7 +167,7 @@ export default function ChatRoomPage() {
           edited_at: null,
           created_at: new Date(),
           updated_at: new Date(),
-          media_files: [],
+          media_files: (event.media_files ?? []) as never,
           reactions: [],
         });
       } else if (event.type === "delete_chat_message") {
@@ -140,14 +199,27 @@ export default function ChatRoomPage() {
     if (status === "open") sendMarkRead();
   }, [status, sendMarkRead]);
 
-  // Auto-scroll to bottom and mark chat as read when new messages arrive.
+  // Auto-scroll to bottom when new messages arrive.
+  // Suppressed while chasing a reply-jump so both effects don't fight each other.
   useEffect(() => {
-    bottomRef.current?.scrollIntoView({ behavior: "auto" });
+    if (!pendingScrollId) {
+      bottomRef.current?.scrollIntoView({ behavior: "auto" });
+    }
     if (status === "open") sendMarkRead();
   // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [messages.length]);
 
-  function handleSend(text: string, replyToId?: number): boolean {
+  async function handleSend(text: string, replyToId?: number, files?: File[]): Promise<boolean> {
+    // Files must go via HTTP multipart; WS handles text-only messages.
+    if (files?.length) {
+      try {
+        const msg = await sendChatMessage({ chatId, content: text || undefined, replyToId, files });
+        appendMessage(msg); // WS broadcast will deduplicate via the id-check in appendMessage
+        return true;
+      } catch {
+        return false;
+      }
+    }
     return replyToId ? sendReply(text, replyToId) : sendMessage(text);
   }
 
@@ -214,6 +286,35 @@ export default function ChatRoomPage() {
           <EmptyState message={t("chat.room.noMessages")} />
         )}
 
+        {/* Beginning-of-chat banner — shown only once all pages are confirmed loaded */}
+        {!hasNextPage && !isLoading && messages.length > 0 && chat && (
+          <div className="flex flex-col items-center gap-3 px-6 py-10 text-center">
+            <Avatar
+              name={chat.name ?? `Chat ${chatId}`}
+              src={chat.icon ?? undefined}
+              size={72}
+            />
+            <div>
+              <p className="text-base font-bold text-brand-text">
+                {chat.name || `Chat #${chatId}`}
+              </p>
+              <p className="mt-1 text-xs text-brand-text/50">
+                {t("chat.room.chatBeginning")}
+              </p>
+              <p className="mt-0.5 text-xs text-brand-text/40">
+                {t("chat.room.chatCreated", {
+                  date: new Date(chat.created_at).toLocaleDateString("cs-CZ", {
+                    day: "numeric",
+                    month: "long",
+                    year: "numeric",
+                  }),
+                })}
+              </p>
+            </div>
+            <div className="h-px w-24 bg-brand-lines/20" />
+          </div>
+        )}
+
         {messages.map((m) => (
           <Message
             key={m.id}
@@ -221,6 +322,8 @@ export default function ChatRoomPage() {
             chat={chat ?? null}
             onReply={setReplyTo}
             onReact={(msg, emoji) => sendReaction(msg.id, emoji)}
+            highlighted={m.id === highlightedId}
+            onScrollToMessage={scrollToMessage}
           />
         ))}