ChatPage: allow selecting a chat on mobile

app/soapbox/features/chats/components/chat-page/chat-page.tsx

@@ -1,21 +1,30 @@
+import classNames from 'clsx';
 import React from 'react';
 
 import { Card, Stack } from 'soapbox/components/ui';
+import { useChatContext } from 'soapbox/contexts/chat-context';
 
 import ChatPageMain from './components/chat-page-main';
 import ChatPageSidebar from './components/chat-page-sidebar';
 
 const ChatPage = () => {
+  const { chat } = useChatContext();
+
   return (
     <Card className='p-0 h-[calc(100vh-109px)] sm:h-[calc(100vh-176px)] overflow-hidden' variant='rounded'>
       <div className='grid grid-cols-9 overflow-hidden h-full dark:divide-x-2 dark:divide-solid dark:divide-gray-800'>
         <Stack
-          className='col-span-9 sm:col-span-3 p-6 bg-gradient-to-r from-white to-gray-100 dark:bg-gray-900 dark:bg-none overflow-hidden dark:inset'
+          className={classNames('col-span-9 sm:col-span-3 p-6 bg-gradient-to-r from-white to-gray-100 dark:bg-gray-900 dark:bg-none overflow-hidden dark:inset', {
+            'hidden sm:block': chat,
+          })}
         >
           <ChatPageSidebar />
         </Stack>
 
-        <Stack className='hidden sm:block col-span-6 h-full overflow-hidden'>
+        <Stack className={classNames('col-span-9 sm:col-span-6 h-full overflow-hidden', {
+          'hidden sm:block': !chat,
+        })}
+        >
           <ChatPageMain />
         </Stack>
       </div>