fix(mobile): prevent bottom padding removal on input focus

src/components/app/AppContent.tsx

@@ -106,7 +106,7 @@ export default function AppContent() {
         </div>
       )}
 
-      <div className={`flex-1 flex flex-col min-w-0 ${isMobile && !isInputFocused ? 'pb-mobile-nav' : ''}`}>
+      <div className={`flex-1 flex flex-col min-w-0 ${isMobile ? 'pb-mobile-nav' : ''}`}>
         <MainContent
           selectedProject={selectedProject}
           selectedSession={selectedSession}

src/components/chat/hooks/useChatComposerState.ts

@@ -903,8 +903,11 @@ export function useChatComposerState({
     [sendMessage, setClaudeStatus, setPendingPermissionRequests],
   );
 
+  const [isInputFocused, setIsInputFocused] = useState(false);
+
   const handleInputFocusChange = useCallback(
     (focused: boolean) => {
+      setIsInputFocused(focused);
       onInputFocusChange?.(focused);
     },
     [onInputFocusChange],
@@ -953,5 +956,6 @@ export function useChatComposerState({
     handlePermissionDecision,
     handleGrantToolPermission,
     handleInputFocusChange,
+    isInputFocused,
   };
 }

src/components/chat/tools/components/CollapsibleSection.tsx

@@ -24,7 +24,7 @@ export const CollapsibleSection: React.FC<CollapsibleSectionProps> = ({
 }) => {
   return (
     <details className={`relative group/details ${className}`} open={open}>
-      <summary className="flex items-center gap-1.5 text-xs cursor-pointer py-0.5 select-none">
+      <summary className="flex items-center gap-1.5 text-xs cursor-pointer py-0.5 select-none group-open/details:sticky group-open/details:top-0 group-open/details:z-10 group-open/details:bg-background group-open/details:-mx-1 group-open/details:px-1">
         <svg
           className="w-3 h-3 text-gray-400 dark:text-gray-500 transition-transform duration-150 group-open/details:rotate-90 flex-shrink-0"
           fill="none"

src/components/chat/view/ChatInterface.tsx

@@ -163,6 +163,7 @@ function ChatInterface({
     handlePermissionDecision,
     handleGrantToolPermission,
     handleInputFocusChange,
+    isInputFocused,
   } = useChatComposerState({
     selectedProject,
     selectedSession,
@@ -373,6 +374,7 @@ function ChatInterface({
           onTextareaScrollSync={syncInputOverlayScroll}
           onTextareaInput={handleTextareaInput}
           onInputFocusChange={handleInputFocusChange}
+          isInputFocused={isInputFocused}
           placeholder={t('input.placeholder', {
             provider:
               provider === 'cursor'

src/components/chat/view/subcomponents/ChatComposer.tsx

@@ -87,6 +87,7 @@ interface ChatComposerProps {
   onTextareaScrollSync: (target: HTMLTextAreaElement) => void;
   onTextareaInput: (event: FormEvent<HTMLTextAreaElement>) => void;
   onInputFocusChange?: (focused: boolean) => void;
+  isInputFocused?: boolean;
   placeholder: string;
   isTextareaExpanded: boolean;
   sendByCtrlEnter?: boolean;
@@ -143,6 +144,7 @@ export default function ChatComposer({
   onTextareaScrollSync,
   onTextareaInput,
   onInputFocusChange,
+  isInputFocused,
   placeholder,
   isTextareaExpanded,
   sendByCtrlEnter,
@@ -162,8 +164,13 @@ export default function ChatComposer({
     (r) => r.toolName === 'AskUserQuestion'
   );
 
+  // On mobile, when input is focused, float the input box at the bottom
+  const mobileFloatingClass = isInputFocused
+    ? 'max-sm:fixed max-sm:bottom-0 max-sm:left-0 max-sm:right-0 max-sm:z-50 max-sm:bg-background max-sm:shadow-[0_-4px_20px_rgba(0,0,0,0.15)]'
+    : '';
+
   return (
-    <div className="p-2 sm:p-4 md:p-4 flex-shrink-0 pb-2 sm:pb-4 md:pb-6">
+    <div className={`p-2 sm:p-4 md:p-4 flex-shrink-0 pb-2 sm:pb-4 md:pb-6 ${mobileFloatingClass}`}>
       {!hasQuestionPanel && (
         <div className="flex-1">
           <ClaudeStatus

src/components/main-content/view/subcomponents/MainContentTitle.tsx

@@ -62,8 +62,8 @@ export default function MainContentTitle({
           </div>
         ) : showChatNewSession ? (
           <div className="min-w-0">
-            <h2 className="text-sm font-semibold text-foreground leading-tight">{t('mainContent.newSession')}</h2>
+            <h2 className="text-base font-semibold text-foreground leading-tight">{t('mainContent.newSession')}</h2>
-            <div className="text-[11px] text-muted-foreground truncate leading-tight">{selectedProject.displayName}</div>
+            <div className="text-xs text-muted-foreground truncate leading-tight">{selectedProject.displayName}</div>
           </div>
         ) : (
           <div className="min-w-0">