Replace PicoCSS with DaisyUI + Tailwind v4

Use gotailwind (standalone Tailwind v4 via Go tool) with DaisyUI
plugin files — no npm needed. CSS is compiled at build time and
embedded via a Via Plugin that serves it as a static file.

Custom "connect4" theme: light, warm, playful palette with red/yellow
accents matching game pieces and board blue accent.

ui/lobby.go

@@ -12,84 +12,83 @@ func LobbyView(nicknameBind, createGameKeyDown, createGameClick h.H, isLoggedIn
 		authSection = GuestBanner()
 	}
 
-	return h.Main(h.Class("container"),
-		h.Div(h.Class("lobby"),
-			authSection,
-			h.H1(h.Text("Connect 4")),
-			h.P(h.Text("Challenge a friend to a game of Connect 4!")),
-			h.Form(
-				h.FieldSet(
-					h.Label(h.Text("Your Nickname"), h.Attr("for", "nickname")),
-					h.Input(
-						h.ID("nickname"),
-						h.Type("text"),
-						h.Placeholder("Enter your nickname"),
-						nicknameBind,
-						h.Attr("required"),
-						createGameKeyDown,
-					),
-				),
-				h.Button(
-					h.Type("button"),
-					h.Text("Create Game"),
-					createGameClick,
+	return h.Main(h.Class("max-w-sm mx-auto mt-8 text-center"),
+		authSection,
+		h.H1(h.Class("text-3xl font-bold"), h.Text("Connect 4")),
+		h.P(h.Class("mb-4"), h.Text("Challenge a friend to a game of Connect 4!")),
+		h.Form(
+			h.FieldSet(h.Class("fieldset"),
+				h.Label(h.Class("label"), h.Text("Your Nickname"), h.Attr("for", "nickname")),
+				h.Input(
+					h.Class("input input-bordered w-full"),
+					h.ID("nickname"),
+					h.Type("text"),
+					h.Placeholder("Enter your nickname"),
+					nicknameBind,
+					h.Attr("required"),
+					createGameKeyDown,
 				),
 			),
-			GameList(userGames, deleteGameClick),
+			h.Button(
+				h.Class("btn btn-primary w-full"),
+				h.Type("button"),
+				h.Text("Create Game"),
+				createGameClick,
+			),
 		),
+		GameList(userGames, deleteGameClick),
 	)
 }
 
 func NicknamePrompt(nicknameBind, setNicknameKeyDown, setNicknameClick h.H) h.H {
-	return h.Main(h.Class("container"),
-		h.Div(h.Class("lobby"),
-			h.H1(h.Text("Join Game")),
-			h.P(h.Text("Enter your nickname to join the game.")),
-			h.Form(
-				h.FieldSet(
-					h.Label(h.Text("Your Nickname"), h.Attr("for", "nickname")),
-					h.Input(
-						h.ID("nickname"),
-						h.Type("text"),
-						h.Placeholder("Enter your nickname"),
-						nicknameBind,
-						h.Attr("required"),
-						h.Attr("autofocus"),
-						setNicknameKeyDown,
-					),
-				),
-				h.Button(
-					h.Type("button"),
-					h.Text("Join"),
-					setNicknameClick,
+	return h.Main(h.Class("max-w-sm mx-auto mt-8 text-center"),
+		h.H1(h.Class("text-3xl font-bold"), h.Text("Join Game")),
+		h.P(h.Class("mb-4"), h.Text("Enter your nickname to join the game.")),
+		h.Form(
+			h.FieldSet(h.Class("fieldset"),
+				h.Label(h.Class("label"), h.Text("Your Nickname"), h.Attr("for", "nickname")),
+				h.Input(
+					h.Class("input input-bordered w-full"),
+					h.ID("nickname"),
+					h.Type("text"),
+					h.Placeholder("Enter your nickname"),
+					nicknameBind,
+					h.Attr("required"),
+					h.Attr("autofocus"),
+					setNicknameKeyDown,
 				),
 			),
+			h.Button(
+				h.Class("btn btn-primary w-full"),
+				h.Type("button"),
+				h.Text("Join"),
+				setNicknameClick,
+			),
 		),
 	)
 }
 
 func GameJoinPrompt(loginClick, guestClick, registerClick h.H) h.H {
-	return h.Main(h.Class("container"),
-		h.Div(h.Class("lobby"),
-			h.H1(h.Text("Join Game")),
-			h.P(h.Text("Log in to track your game history, or continue as a guest.")),
-			h.Div(h.Class("join-options"),
-				h.Button(
-					h.Type("button"),
-					h.Text("Login"),
-					loginClick,
-				),
-				h.Button(
-					h.Type("button"),
-					h.Class("secondary"),
-					h.Text("Continue as Guest"),
-					guestClick,
-				),
+	return h.Main(h.Class("max-w-sm mx-auto mt-8 text-center"),
+		h.H1(h.Class("text-3xl font-bold"), h.Text("Join Game")),
+		h.P(h.Class("mb-4"), h.Text("Log in to track your game history, or continue as a guest.")),
+		h.Div(h.Class("flex flex-col gap-2 my-4"),
+			h.Button(
+				h.Class("btn btn-primary w-full"),
+				h.Type("button"),
+				h.Text("Login"),
+				loginClick,
 			),
-			h.P(h.Class("register-link"),
-				h.Text("Don't have an account? "),
-				h.A(h.Href("#"), h.Text("Register"), registerClick),
+			h.Button(
+				h.Class("btn btn-secondary w-full"),
+				h.Type("button"),
+				h.Text("Continue as Guest"),
+				guestClick,
 			),
 		),
+		h.P(h.Class("text-sm opacity-60"),
+			h.Text("Don't have an account? "),
+			h.A(h.Class("link"), h.Href("#"), h.Text("Register"), registerClick),
+		),
 	)
 }