deploy sd35m: 40 pairs

app/main.py

@@ -137,10 +137,12 @@ async def submit(req: Request):
         for v in votes:
             p = PAIRS.get(int(v.get("pair_id", -1)))
             ch = v.get("choice")
-            if not p or ch not in ("left", "right"):
+            if not p or ch not in ("left", "right", "cannot"):
                 continue
             if p["kind"] == "catch":
                 gc = int(ch == p["correct_side"]); n_catch += 1; n_pass += gc
+            elif ch == "cannot":
+                gc = None   # "Cannot decide" → tie / no preference (excluded from win-rate denominator)
             else:
                 gc = int(ch == p["guided_side"])
             if record:   # opt-out: skip persisting votes (results still shown to the participant)

app/static/index.html

@@ -47,11 +47,14 @@
     <div class="mut"><span id="pos">1</span> / <span id="total">0</span></div>
     <div class="bar"><div id="prog"></div></div>
     <div class="prompt">“<span id="prompt"></span>”</div>
-    <p class="hint">Click the image you prefer.</p>
+    <p class="hint">Click the image you prefer — or “Cannot decide” if they look equally good.</p>
     <div class="pair">
       <div class="opt" id="optL"><img id="imgL"><div class="tag">IMAGE 1</div></div>
       <div class="opt" id="optR"><img id="imgR"><div class="tag">IMAGE 2</div></div>
     </div>
+    <div class="center" style="margin-top:14px">
+      <button class="primary" id="optC" style="background:#3a3f48">Cannot decide</button>
+    </div>
   </div>
 
   <div id="done" class="card hide">
@@ -121,10 +124,12 @@ $("start").onclick=start;
 $("email").addEventListener("keydown",e=>{ if(e.key==="Enter") start(); });
 $("optL").onclick=()=>choose("left");
 $("optR").onclick=()=>choose("right");
+$("optC").onclick=()=>choose("cannot");
 document.addEventListener("keydown",e=>{
   if($("study").classList.contains("hide")) return;
   if(e.key==="ArrowLeft"||e.key==="a"||e.key==="A") choose("left");
   if(e.key==="ArrowRight"||e.key==="b"||e.key==="B") choose("right");
+  if(e.key==="c"||e.key==="C"||e.key==="ArrowDown"||e.key===" ") { e.preventDefault(); choose("cannot"); }
 });
 </script>
 </body>