diff --git a/ROADMAP.md b/ROADMAP.md
index 1c9997f..c5533f8 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -17,6 +17,7 @@
 
 ## Phase 3 — Polish
 
+- [x] Responsive terminal layout (adaptive sidebar, truncation, resize)
 - [ ] Channel tree navigation
 - [ ] User list with status indicators
 - [ ] Volume control
diff --git a/src/tuimble/app.py b/src/tuimble/app.py
index ecb2b52..18520b5 100644
--- a/src/tuimble/app.py
+++ b/src/tuimble/app.py
@@ -56,21 +56,35 @@ class StatusBar(Static):
     server_info = reactive("")
 
     def render(self) -> str:
+        w = self.size.width if self.size.width > 0 else 80
+
         if self.connected:
-            conn = "[#9ece6a]\u25cf[/] connected"
+            conn_sym = "[#9ece6a]\u25cf[/]"
+            conn_full = f"{conn_sym} connected"
         else:
-            conn = "[#f7768e]\u25cb[/] disconnected"
+            conn_sym = "[#f7768e]\u25cb[/]"
+            conn_full = f"{conn_sym} disconnected"
+
         if self.ptt_active:
-            ptt = "[#e0af68]\u25cf[/] TX"
+            ptt_sym = "[#e0af68]\u25cf[/]"
+            ptt_full = f"{ptt_sym} TX"
         else:
-            ptt = "[#565f89]\u25cb[/] idle"
+            ptt_sym = "[#565f89]\u25cb[/]"
+            ptt_full = f"{ptt_sym} idle"
+
+        if w < 40:
+            return f" {conn_sym} {ptt_sym}"
+        if w < 60:
+            return f" {conn_full}  {ptt_full}"
         info = f"  [dim]{self.server_info}[/]" if self.server_info else ""
-        return f" {conn}  {ptt}{info}"
+        return f" {conn_full}  {ptt_full}{info}"
 
 
 class ChannelTree(Static):
     """Channel and user list."""
 
+    DEFAULT_WIDTH = 24
+
     def __init__(self, **kwargs) -> None:
         super().__init__(**kwargs)
         self._channels: dict[int, Channel] = {}
@@ -90,6 +104,23 @@ class ChannelTree(Static):
         self._users_by_channel = {}
         self.refresh()
 
+    @property
+    def _available_width(self) -> int:
+        """Usable character width, accounting for padding."""
+        w = self.size.width if self.size.width > 0 else self.DEFAULT_WIDTH
+        return max(w, 12)
+
+    @staticmethod
+    def _truncate(text: str, max_width: int) -> str:
+        """Clip text with ellipsis if it exceeds max_width."""
+        if max_width < 1:
+            return ""
+        if len(text) <= max_width:
+            return text
+        if max_width <= 3:
+            return text[:max_width]
+        return text[: max_width - 3] + "..."
+
     def render(self) -> str:
         if not self._channels:
             return " Channels\n [dim]\u2514\u2500 (not connected)[/]"
@@ -116,9 +147,13 @@ class ChannelTree(Static):
         if ch is None:
             return
 
+        w = self._available_width
         prefix = " " * indent
         branch = "\u2514\u2500" if is_last else "\u251c\u2500"
-        lines.append(f"{prefix}{branch} [bold]{ch.name}[/]")
+        # indent + 2 branch chars + 1 space
+        name_max = w - indent - 3
+        name = self._truncate(ch.name, name_max)
+        lines.append(f"{prefix}{branch} [bold]{name}[/]")
 
         users = self._users_by_channel.get(channel_id, [])
         children = [
@@ -127,11 +162,15 @@ class ChannelTree(Static):
             if c.parent_id == channel_id and c.channel_id != channel_id
         ]
 
-        sub_prefix = " " * (indent + 2)
+        sub_indent = indent + 2
+        sub_prefix = " " * sub_indent
+        # sub_indent + 2 bullet chars + 1 space
+        user_max = w - sub_indent - 3
         for i, user_name in enumerate(users):
             is_last_item = i == len(users) - 1 and not children
             bullet = "\u2514\u2500" if is_last_item else "\u251c\u2500"
-            lines.append(f"{sub_prefix}{bullet} [#7aa2f7]{user_name}[/]")
+            uname = self._truncate(user_name, user_max)
+            lines.append(f"{sub_prefix}{bullet} [#7aa2f7]{uname}[/]")
 
         for i, child in enumerate(children):
             self._render_tree(
@@ -164,9 +203,12 @@ class TuimbleApp(App):
         height: 1fr;
     }
     #sidebar {
-        width: 24;
+        width: auto;
+        min-width: 16;
+        max-width: 32;
         border-right: solid #292e42;
         padding: 0 1;
+        overflow: hidden;
     }
     #chat-area {
         width: 1fr;
@@ -385,6 +427,13 @@ class TuimbleApp(App):
         status = self.query_one("#status", StatusBar)
         status.ptt_active = transmitting
 
+    # -- resize --------------------------------------------------------------
+
+    def on_resize(self, _event: events.Resize) -> None:
+        """Refresh width-aware widgets when terminal resizes."""
+        self.query_one("#sidebar", ChannelTree).refresh()
+        self.query_one("#status", StatusBar).refresh()
+
     # -- lifecycle -----------------------------------------------------------
 
     def action_quit(self) -> None: