diff --git a/apps/web/src/components/ChatInput.tsx b/apps/web/src/components/ChatInput.tsx
index 22baf48..3de3c8c 100644
--- a/apps/web/src/components/ChatInput.tsx
+++ b/apps/web/src/components/ChatInput.tsx
@@ -9,6 +9,7 @@ import { AttachmentPreviewModal } from '@/components/AttachmentPreviewModal';
 import { FileMentionPopover } from '@/components/FileMentionPopover';
 import { api } from '@/api/client';
 import { sessionEvents } from '@/hooks/sessionEvents';
+import { useViewport } from '@/hooks/useViewport';
 
 interface Props {
   disabled?: boolean;
@@ -18,6 +19,7 @@ interface Props {
 }
 
 export function ChatInput({ disabled, projectId, onSend, onForceSend }: Props) {
+  const { isMobile } = useViewport();
   const [value, setValue] = useState('');
   const [busy, setBusy] = useState(false);
   const [attachments, setAttachments] = useState<Attachment[]>([]);
@@ -185,6 +187,11 @@ export function ChatInput({ disabled, projectId, onSend, onForceSend }: Props) {
 
   function onKeyDown(e: KeyboardEvent<HTMLTextAreaElement>) {
     if (mentionState?.open) return;
+    // IME safety: never act on Enter while an IME composition is in flight
+    // (CJK input methods commit composition via Enter). Without this, the
+    // first Enter of a Japanese/Chinese/Korean composition would submit
+    // instead of finalizing the candidate.
+    if (e.nativeEvent.isComposing) return;
     if (e.key === 'Enter' && e.shiftKey && (e.metaKey || e.ctrlKey) && onForceSend) {
       e.preventDefault();
       void forceSubmit();
@@ -195,7 +202,9 @@ export function ChatInput({ disabled, projectId, onSend, onForceSend }: Props) {
       void submit();
       return;
     }
-    if (e.key === 'Enter' && !e.shiftKey) {
+    // Bare Enter: sends on desktop, inserts a newline on mobile (per spec —
+    // send is via the dedicated button on touch devices).
+    if (e.key === 'Enter' && !e.shiftKey && !isMobile) {
       e.preventDefault();
       void submit();
     }
@@ -219,7 +228,7 @@ export function ChatInput({ disabled, projectId, onSend, onForceSend }: Props) {
   }
 
   return (
-    <div className="border-t">
+    <div className="border-t" style={{ paddingBottom: 'env(safe-area-inset-bottom)' }}>
       <div className="max-w-[1000px] mx-auto w-full">
       {attachments.length > 0 && (
         <div className="flex flex-wrap gap-1.5 px-4 pt-3">
@@ -239,7 +248,11 @@ export function ChatInput({ disabled, projectId, onSend, onForceSend }: Props) {
           value={value}
           onChange={handleChange}
           onKeyDown={onKeyDown}
-          placeholder="Ask about this project. Enter to send, Shift+Enter for newline."
+          placeholder={
+            isMobile
+              ? 'Ask about this project. Tap send to submit.'
+              : 'Ask about this project. Enter to send · Shift+Enter for newline.'
+          }
           disabled={disabled || busy}
           rows={3}
           className="resize-none min-h-[68px] max-h-[240px]"
diff --git a/apps/web/src/components/ChatTabBar.tsx b/apps/web/src/components/ChatTabBar.tsx
index dbb63cf..6a730b1 100644
--- a/apps/web/src/components/ChatTabBar.tsx
+++ b/apps/web/src/components/ChatTabBar.tsx
@@ -115,7 +115,7 @@ export function ChatTabBar({
                     e.stopPropagation();
                     onRemoveTab(chat.id);
                   }}
-                  className="p-0.5 hover:bg-muted rounded opacity-0 group-hover:opacity-60 hover:!opacity-100 shrink-0"
+                  className="inline-flex items-center justify-center p-0.5 hover:bg-muted rounded opacity-0 group-hover:opacity-60 hover:!opacity-100 shrink-0 max-md:min-h-[44px] max-md:min-w-[44px] max-md:opacity-100"
                   aria-label="Close tab"
                 >
                   <X size={10} />
@@ -161,7 +161,7 @@ export function ChatTabBar({
         <button
           type="button"
           onClick={onNewChat}
-          className="p-1 rounded text-muted-foreground hover:bg-muted hover:text-foreground"
+          className="inline-flex items-center justify-center p-1 rounded text-muted-foreground hover:bg-muted hover:text-foreground max-md:min-h-[44px] max-md:min-w-[44px]"
           aria-label="New chat"
           title="New chat"
         >
@@ -171,7 +171,7 @@ export function ChatTabBar({
           type="button"
           onClick={onShowHistory}
           className={cn(
-            'p-1 rounded text-muted-foreground hover:bg-muted hover:text-foreground',
+            'inline-flex items-center justify-center p-1 rounded text-muted-foreground hover:bg-muted hover:text-foreground max-md:min-h-[44px] max-md:min-w-[44px]',
             pane.kind === 'empty' && 'text-foreground bg-muted/50'
           )}
           aria-label="Session history"
@@ -183,7 +183,7 @@ export function ChatTabBar({
           <button
             type="button"
             onClick={onRemovePane}
-            className="p-1 rounded text-muted-foreground hover:bg-muted hover:text-foreground"
+            className="inline-flex items-center justify-center p-1 rounded text-muted-foreground hover:bg-muted hover:text-foreground max-md:min-h-[44px] max-md:min-w-[44px]"
             aria-label="Close pane"
             title="Close pane"
           >
diff --git a/apps/web/src/components/MessageBubble.tsx b/apps/web/src/components/MessageBubble.tsx
index 2ac9fb4..34f9156 100644
--- a/apps/web/src/components/MessageBubble.tsx
+++ b/apps/web/src/components/MessageBubble.tsx
@@ -266,11 +266,11 @@ function ActionRow({
 
   return (
     <>
-      <div className="flex gap-1 opacity-0 group-hover:opacity-100 transition-opacity">
+      <div className="flex gap-1 opacity-0 group-hover:opacity-100 transition-opacity max-md:opacity-100">
         <button
           type="button"
           onClick={() => void copy()}
-          className="inline-flex items-center justify-center size-6 rounded text-muted-foreground hover:bg-muted hover:text-foreground"
+          className="inline-flex items-center justify-center size-6 rounded text-muted-foreground hover:bg-muted hover:text-foreground max-md:min-h-[44px] max-md:min-w-[44px]"
           aria-label="Copy message"
           title="Copy"
         >
@@ -281,7 +281,7 @@ function ActionRow({
             type="button"
             onClick={() => void regenerate()}
             disabled={!canRegen || regenerating}
-            className="inline-flex items-center justify-center size-6 rounded text-muted-foreground hover:bg-muted hover:text-foreground disabled:opacity-40 disabled:cursor-not-allowed"
+            className="inline-flex items-center justify-center size-6 rounded text-muted-foreground hover:bg-muted hover:text-foreground disabled:opacity-40 disabled:cursor-not-allowed max-md:min-h-[44px] max-md:min-w-[44px]"
             aria-label="Regenerate message"
             title="Regenerate"
           >
@@ -292,7 +292,7 @@ function ActionRow({
           type="button"
           onClick={() => void fork()}
           disabled={!canFork || forking}
-          className="inline-flex items-center justify-center size-6 rounded text-muted-foreground hover:bg-muted hover:text-foreground disabled:opacity-40 disabled:cursor-not-allowed"
+          className="inline-flex items-center justify-center size-6 rounded text-muted-foreground hover:bg-muted hover:text-foreground disabled:opacity-40 disabled:cursor-not-allowed max-md:min-h-[44px] max-md:min-w-[44px]"
           aria-label="Fork from here"
           title="Fork from here"
         >
@@ -302,7 +302,7 @@ function ActionRow({
           type="button"
           onClick={() => setDeleteOpen(true)}
           disabled={!canDelete}
-          className="inline-flex items-center justify-center size-6 rounded text-muted-foreground hover:bg-muted hover:text-destructive disabled:opacity-40 disabled:cursor-not-allowed"
+          className="inline-flex items-center justify-center size-6 rounded text-muted-foreground hover:bg-muted hover:text-destructive disabled:opacity-40 disabled:cursor-not-allowed max-md:min-h-[44px] max-md:min-w-[44px]"
           aria-label="Delete message"
           title="Delete message"
         >
@@ -476,7 +476,7 @@ export function MessageBubble({ message, sessionChats }: Props) {
   if (message.role === 'user') {
     return (
       <div className="group flex flex-col items-end gap-1">
-        <div className="max-w-[80%] rounded-lg bg-primary text-primary-foreground px-3 py-2 text-sm whitespace-pre-wrap">
+        <div className="max-w-[80%] rounded-lg bg-primary text-primary-foreground px-3 py-2 text-sm whitespace-pre-wrap break-words min-w-0">
           {message.content}
         </div>
         <ActionRow message={message} />
@@ -495,7 +495,7 @@ export function MessageBubble({ message, sessionChats }: Props) {
         <ToolCallCard key={tc.id} toolCall={tc} />
       ))}
       {(hasContent || (!hasToolCalls && isStreaming)) && (
-        <div className="max-w-[90%] text-sm leading-relaxed space-y-2">
+        <div className="max-w-[90%] text-sm leading-relaxed space-y-2 break-words min-w-0">
           {hasContent ? <MarkdownBody content={message.content} /> : null}
           {isStreaming && (
             <span className="inline-block w-1.5 h-3.5 align-baseline bg-muted-foreground/60 animate-pulse" />
diff --git a/apps/web/src/components/panes/ChatPane.tsx b/apps/web/src/components/panes/ChatPane.tsx
index b858954..95abe8d 100644
--- a/apps/web/src/components/panes/ChatPane.tsx
+++ b/apps/web/src/components/panes/ChatPane.tsx
@@ -120,7 +120,7 @@ export function ChatPane({ sessionId, chatId, projectId, sessionChats }: Props)
                 <DropdownMenuTrigger asChild>
                   <button
                     type="button"
-                    className="p-0.5 hover:bg-muted rounded shrink-0"
+                    className="inline-flex items-center justify-center p-0.5 hover:bg-muted rounded shrink-0 max-md:min-h-[44px] max-md:min-w-[44px]"
                     aria-label="Queued message options"
                   >
                     <ChevronDown size={12} />
@@ -138,7 +138,7 @@ export function ChatPane({ sessionId, chatId, projectId, sessionChats }: Props)
               <button
                 type="button"
                 onClick={() => removeQueued(i)}
-                className="p-0.5 hover:bg-muted rounded shrink-0"
+                className="inline-flex items-center justify-center p-0.5 hover:bg-muted rounded shrink-0 max-md:min-h-[44px] max-md:min-w-[44px]"
                 aria-label="Cancel queued message"
               >
                 <X size={12} />
@@ -156,7 +156,7 @@ export function ChatPane({ sessionId, chatId, projectId, sessionChats }: Props)
           <button
             type="button"
             onClick={() => void handleStop()}
-            className="flex items-center gap-1.5 text-xs px-3 py-1 rounded-full border hover:bg-muted text-muted-foreground hover:text-foreground"
+            className="flex items-center gap-1.5 text-xs px-3 py-1 rounded-full border hover:bg-muted text-muted-foreground hover:text-foreground max-md:min-h-[44px] max-md:px-5"
           >
             <Square size={10} className="fill-current" />
             Stop generating