diff --git a/index.html b/index.html
index f9fa70f..620bcc6 100644
--- a/index.html
+++ b/index.html
@@ -36,7 +36,9 @@
   <div class="mx-auto w-full max-w-none px-0">
     <form id="composer" class="group relative flex items-end gap-2 px-4">
       <textarea id="input" rows="1" placeholder="Send a message" spellcheck="false" autocapitalize="none" autocomplete="off" autocorrect="off" inputmode="text" enterkeyhint="send" class="flex-1 resize-none rounded-2xl border border-gray-300 bg-white px-4 py-3 text-[14px] leading-6 placeholder:text-gray-400 focus:outline-none focus:ring-2 focus:ring-black/20 focus:border-gray-300 max-h-40 overflow-hidden"></textarea>
-      <button id="sendBtn" type="submit" aria-label="Send" class="shrink-0 rounded-2xl bg-black text-white h-10 w-10 inline-flex items-center justify-center shadow-sm hover:bg-black/90 active:scale-[.98] transition"><svg viewBox="0 0 24 24" class="h-5 w-5" fill="none" stroke="currentColor" stroke-width="1.8"><path stroke-linecap="round" stroke-linejoin="round" d="M5 12h14M12 5l7 7-7 7"/></svg></button>
+      <button id="sendBtn" type="submit" aria-label="Send" class="shrink-0 rounded-2xl bg-black text-white h-10 w-10 inline-flex items-center justify-center shadow-sm hover:bg-black/90 active:scale-[.98] transition">
+        <i data-lucide="sparkles" class="h-5 w-5"></i>
+      </button>
     </form>
   </div>
 </footer>
@@ -108,7 +110,7 @@
 <script src="https://cdn.jsdelivr.net/npm/markdown-it@13.0.1/dist/markdown-it.min.js"></script>
 <script src="https://cdn.jsdelivr.net/gh/highlightjs/cdn-release@11.9.0/build/highlight.min.js"></script>
 <script>
-const DEFAULT_MODEL='openai/gpt-4o',DEFAULT_API_KEY=''
+const DEFAULT_MODEL='openai/gpt-5-chat',DEFAULT_API_KEY=''
 const el=Object.fromEntries(['chat','messages','composer','input','sendBtn','settingsBtnTop','settingsModal','settingsForm','closeSettings','cancelSettings','tabModel','tabPrompt','panelModel','panelPrompt','set_model','set_temperature','set_top_p','set_top_k','set_frequency_penalty','set_presence_penalty','set_repetition_penalty','set_min_p','set_top_a','set_system_prompt','deleteSuneBtn','sidebar','sidebarOverlay','sidebarBtn','suneList','newSuneBtn','userMenuBtn','userMenu','apiKeyOption','sunesImportOption','sunesExportOption','threadsImportOption','threadsExportOption','threadsDedupOption','importInput','historyBtn','historyPanel','historyOverlay','historyList','closeHistory','historyMenu','suneMenu','footer'].map(id=>[id,document.getElementById(id)]))
 const clamp=(v,min,max)=>Math.max(min,Math.min(max,v)),num=(v,d)=>v==null||v===''||isNaN(+v)?d:+v,int=(v,d)=>v==null||v===''||isNaN(parseInt(v))?d:parseInt(v),gid=()=>Math.random().toString(36).slice(2,9),esc=s=>String(s).replace(/[&<>'"`]/g,c=>({"&":"&amp;","<":"&lt;",">":"&gt;","\"":"&quot;","'":"&#39;","`":"&#96;"}[c]))
 const globalStore={get apiKey(){return localStorage.getItem('openrouter_api_key')||DEFAULT_API_KEY||''},set apiKey(v){localStorage.setItem('openrouter_api_key',v||'')}}