diff --git a/src/app/layout.tsx b/src/app/layout.tsx
index 7de9bb6..f751c78 100644
--- a/src/app/layout.tsx
+++ b/src/app/layout.tsx
@@ -3,6 +3,7 @@ import { Geist, Geist_Mono } from "next/font/google";
 import "./globals.css";
 import { TRPCReactProvider } from "@/trpc/client";
 import { Toaster } from "sonner";
+import { ThemeProvider } from "next-themes";
 
 const geistSans = Geist({
   variable: "--font-geist-sans",
@@ -26,12 +27,19 @@ export default function RootLayout({
 }>) {
   return (
     <TRPCReactProvider>
-      <html lang="en">
+      <html lang="en" suppressHydrationWarning>
         <body
           className={`${geistSans.variable} ${geistMono.variable} antialiased`}
         >
-          <Toaster />
-          {children}
+          <ThemeProvider
+            attribute="class"
+            defaultTheme="system"
+            enableSystem
+            disableTransitionOnChange
+          >
+            <Toaster />
+            {children}
+          </ThemeProvider>
         </body>
       </html>
     </TRPCReactProvider>
diff --git a/src/modules/projects/ui/components/message-card.tsx b/src/modules/projects/ui/components/message-card.tsx
index 3c279d0..a0a4c12 100644
--- a/src/modules/projects/ui/components/message-card.tsx
+++ b/src/modules/projects/ui/components/message-card.tsx
@@ -42,9 +42,11 @@ const FragmentCard = ({
     onFragmentClick
 }: FragmentCardProps) => {
     return (
-        <button className={cn(
-            "flex items-start text-start gap-2 border rounded-lg bg-muted w-fit p-3 hover:bg-secondary transition-colors cursor-pointer",
-            isActiveFragment && "bg-primary text-primary-foreground border-primary hover:bg-primary"
+        <button 
+            onClick={() => onFragmentClick(fragment)}
+            className={cn(
+                "flex items-start text-start gap-2 border rounded-lg bg-muted w-fit p-3 hover:bg-secondary transition-colors cursor-pointer",
+                isActiveFragment && "bg-primary text-primary-foreground border-primary hover:bg-primary"
         )}>
             <Code2Icon className="size-4 mt-0.5" />
             <div className="flex flex-col flex-1">
@@ -94,7 +96,7 @@ const AssistantMessage = ({
                     <FragmentCard
                         fragment={fragment}
                         isActiveFragment={isActiveFragment}
-                        onFragmentClick={() => { }}
+                        onFragmentClick={onFragmentClick}
                     />
                 )}
             </div>
@@ -122,7 +124,7 @@ export default function MessageCard({
                 fragment={fragment}
                 createdAt={createdAt}
                 isActiveFragment={isActiveFragment}
-                onFragmentClick={() => { }}
+                onFragmentClick={onFragmentClick}
                 type={type}
             />
         )
diff --git a/src/modules/projects/ui/components/message-loading.tsx b/src/modules/projects/ui/components/message-loading.tsx
new file mode 100644
index 0000000..cd5a00f
--- /dev/null
+++ b/src/modules/projects/ui/components/message-loading.tsx
@@ -0,0 +1,56 @@
+import Image from "next/image";
+import { useEffect, useState } from "react";
+
+const ShimmerMessages = () => {
+    const messages = [
+        "Thinking...", 
+        "Loading...", 
+        "Generating...", 
+        "Analyzing your request...", 
+        "Building your website", 
+        "Crafting components...", 
+        "Optimizing layout...",
+        "Adding final touches...", 
+        "Almost ready..."
+    ]; 
+
+    const [currentMessageIndex, setCurrentMessageIndex] = useState(0);
+
+    useEffect(() => {
+        const interval = setInterval(() => {
+            setCurrentMessageIndex((prev) => (prev + 1) % messages.length);
+        }, 2000); 
+
+        return () => clearInterval(interval);
+    }, [messages.length]);
+
+    return (
+        <div className="flex items-center gap-2">
+            <span className="text-base text-muted-foreground animate-pulse">
+                {messages[currentMessageIndex]}
+            </span>
+        </div>
+    );
+}
+
+export default function MessageLoading() {
+    return (
+        <div className="flex flex-col group px-2 pb-4">
+            <div className="flex items-center gap-2 pl-2 mb-2">
+                <Image 
+                    src="/logo.svg"
+                    alt="Neo logo"
+                    width={15}
+                    height={15}
+                    className="shrink-0"
+                />
+                <span className="text-sm font-medium">
+                    Neo
+                </span>
+            </div>
+            <div className="pl-8.5 flex flex-col gap-y-4">
+                <ShimmerMessages />
+            </div>
+        </div>
+    );
+}
\ No newline at end of file
diff --git a/src/modules/projects/ui/components/messages-container.tsx b/src/modules/projects/ui/components/messages-container.tsx
index 5b50a70..5e171ee 100644
--- a/src/modules/projects/ui/components/messages-container.tsx
+++ b/src/modules/projects/ui/components/messages-container.tsx
@@ -5,23 +5,36 @@ import { useSuspenseQuery } from "@tanstack/react-query";
 import MessageCard from "./message-card";
 import MessageForm from "./message-form";
 import { useEffect, useRef } from "react";
+import { Fragment } from "@/generated/prisma";
+import MessageLoading from "./message-loading";
 
-export default function MessagesContainer({ projectId }: { projectId: string }) {
+export default function MessagesContainer({ 
+    projectId, 
+    activeFragment, 
+    setActiveFragment
+ }: { 
+    projectId: string, 
+    activeFragment: Fragment | null, 
+    setActiveFragment: (fragment: Fragment | null) => void
+ }) {
     const bottomRef = useRef<HTMLDivElement>(null);
     const trpc = useTRPC();
     const { data: messages } = useSuspenseQuery(trpc.messages.getMany.queryOptions({
         projectId: projectId
-    })); 
+    }));
 
     useEffect(() => {
-        const lastAssistantMessage = messages.findLast(
-            (message) => message.role === "ASSISTANT"
+        const lastAssistantMessageWithFragment = messages.findLast(
+            (message) => message.role === "ASSISTANT" && !!message.fragment
         );
 
-        if (lastAssistantMessage) {
-            // TODO: SET ACTIVE FRAGMENT
+        if (lastAssistantMessageWithFragment) {
+            setActiveFragment(lastAssistantMessageWithFragment.fragment); 
         }
-    }, [messages]);
+    }, [messages, setActiveFragment]);
+
+    const lastMessage = messages[messages.length - 1 ]; 
+    const isLastMessageUser = lastMessage?.role === "USER";
 
     useEffect(() => {
         bottomRef.current?.scrollIntoView();
@@ -38,11 +51,12 @@ export default function MessagesContainer({ projectId }: { projectId: string })
                             role={message.role}
                             fragment={message.fragment}
                             createdAt={message.createdAt}
-                            isActiveFragment={false}
-                            onFragmentClick={() => {}}
+                            isActiveFragment={activeFragment?.id === message.fragment?.id}
+                            onFragmentClick={() => setActiveFragment(message.fragment)}
                             type={message.type}
                         />
                     ))}
+                    { isLastMessageUser && <MessageLoading /> }
                     <div ref={bottomRef} />
                 </div>
             </div>
diff --git a/src/modules/projects/ui/components/project-header.tsx b/src/modules/projects/ui/components/project-header.tsx
new file mode 100644
index 0000000..961b3ca
--- /dev/null
+++ b/src/modules/projects/ui/components/project-header.tsx
@@ -0,0 +1,71 @@
+import { Button } from "@/components/ui/button";
+import { DropdownMenu, DropdownMenuContent, DropdownMenuItem, DropdownMenuPortal, DropdownMenuRadioGroup, DropdownMenuRadioItem, DropdownMenuSeparator, DropdownMenuSub, DropdownMenuSubContent, DropdownMenuSubTrigger, DropdownMenuTrigger } from "@/components/ui/dropdown-menu";
+import { useTRPC } from "@/trpc/client";
+import { useSuspenseQuery } from "@tanstack/react-query";
+import { ChevronDownIcon, ChevronLeftIcon, SunMoonIcon } from "lucide-react";
+import { useTheme } from "next-themes";
+import Image from "next/image";
+import Link from "next/link";
+
+export default function ProjectHeader({ projectId }: { projectId: string }) {
+    const trpc = useTRPC();
+    const { data: project } = useSuspenseQuery(
+        trpc.projects.getOne.queryOptions({ id: projectId })
+    );
+
+    const { setTheme, theme } = useTheme();
+
+    return (
+        <header className="p-2 flex justify-between items-center border-b">
+            <DropdownMenu>
+                <DropdownMenuTrigger asChild>
+                    <Button
+                        variant="ghost"
+                        size="sm"
+                        className="focus-visible:ring-0 hover:bg-transparent hover:opacity-75 transition-opacity pl-2!"
+                    >
+                        <Image
+                            src="/logo.svg"
+                            alt="Neo logo"
+                            width={15}
+                            height={15}
+                            className="shrink-0"
+                        />
+                        <span className="text-sm font-medium">{project.name}</span>
+                        <ChevronDownIcon />
+                    </Button>
+                </DropdownMenuTrigger>
+                <DropdownMenuContent>
+                    <DropdownMenuItem asChild>
+                        <Link href="/">
+                            <ChevronLeftIcon />
+                            <span>Go to dashboard</span>
+                        </Link>
+                    </DropdownMenuItem>
+                    <DropdownMenuSeparator />
+                    <DropdownMenuSub>
+                        <DropdownMenuSubTrigger className="gap-2">
+                            <SunMoonIcon className="size-4 text-muted-foreground" />
+                            <span>Appearance</span>
+                        </DropdownMenuSubTrigger>
+                        <DropdownMenuPortal>
+                            <DropdownMenuSubContent>
+                                <DropdownMenuRadioGroup value={theme} onValueChange={setTheme}>
+                                    <DropdownMenuRadioItem value="light">
+                                        <span>Light</span>
+                                    </DropdownMenuRadioItem>
+                                    <DropdownMenuRadioItem value="dark">
+                                        <span>Dark</span>
+                                    </DropdownMenuRadioItem>
+                                    <DropdownMenuRadioItem value="system">
+                                        <span>System</span>
+                                    </DropdownMenuRadioItem>
+                                </DropdownMenuRadioGroup>
+                            </DropdownMenuSubContent>
+                        </DropdownMenuPortal>
+                    </DropdownMenuSub>
+                </DropdownMenuContent>
+            </DropdownMenu>
+        </header>
+    );
+}
\ No newline at end of file
diff --git a/src/modules/projects/ui/views/project-view.tsx b/src/modules/projects/ui/views/project-view.tsx
index 186a4fc..590f398 100644
--- a/src/modules/projects/ui/views/project-view.tsx
+++ b/src/modules/projects/ui/views/project-view.tsx
@@ -8,13 +8,17 @@ import {
   ResizablePanelGroup,
 } from "@/components/ui/resizable"
 import MessagesContainer from "../components/messages-container";
-import { Suspense } from "react";
+import { Suspense, useState } from "react";
+import { Fragment } from "@/generated/prisma";
+import ProjectHeader from "../components/project-header";
 
 interface Props {
     projectId: string
 }
 
 export default function ProjectView({ projectId }: Props) {
+    const [activeFragment, setActiveFragment] = useState<Fragment | null>(null);
+
     return (
         <div className="h-screen">
             <ResizablePanelGroup direction="horizontal">
@@ -23,8 +27,15 @@ export default function ProjectView({ projectId }: Props) {
                     minSize={20}
                     className="flex flex-col min-h-0"    
                 >
+                    <Suspense fallback={<p>Loading project...</p>}>
+                        <ProjectHeader projectId={projectId}/>
+                    </Suspense>
                     <Suspense fallback={<p>Loading messages</p>}>
-                        <MessagesContainer projectId={projectId} />
+                        <MessagesContainer 
+                            projectId={projectId} 
+                            activeFragment={activeFragment}
+                            setActiveFragment={setActiveFragment}
+                        />
                     </Suspense>
                 </ResizablePanel>
                 <ResizableHandle withHandle />
