fix: BITFIELD via raw REST API and improve error handling

- Use Upstash REST API directly for BITFIELD (SDK builder broken in v1.37)
- Add redisRaw() helper for raw command execution
- Wrap setPixels in try-catch, return JSON errors instead of 500 text
- Client handles non-JSON server responses gracefully
- Toolbar: larger 44px touch targets, separators, better contrast

src/client/App.svelte

@@ -81,7 +81,12 @@
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ pixels }),
       });
-      const data = await res.json();
+      const text = await res.text();
+      let data;
+      try { data = JSON.parse(text); } catch {
+        console.error('Server returned non-JSON:', res.status, text);
+        return;
+      }
       if (data.ok) {
         credits = data.credits;
         canvasRenderer.commitPending();

src/client/components/DrawToolbar.svelte

@@ -11,6 +11,8 @@
       title="Draw mode: drag to draw, right-drag to pan">Draw</button>
   </div>
 
+  <div class="sep"></div>
+
   <div class="group">
     <button onclick={onUndo} disabled={!canUndo} title="Undo (Ctrl+Z)">Undo</button>
     <button onclick={onRedo} disabled={!canRedo} title="Redo (Ctrl+Y)">Redo</button>
@@ -18,6 +20,8 @@
       title="Clear all pending pixels">Clear</button>
   </div>
 
+  <div class="sep"></div>
+
   <button class="submit-btn" onclick={onSubmit} disabled={pixelCount === 0 || submitting}>
     {submitting ? 'Sending...' : `Submit${pixelCount > 0 ? ` (${pixelCount})` : ''}`}
   </button>
@@ -26,55 +30,88 @@
 <style>
   .toolbar {
     position: fixed;
-    bottom: 70px;
+    bottom: 80px;
     left: 50%;
     transform: translateX(-50%);
     display: flex;
-    gap: 8px;
+    gap: 6px;
     align-items: center;
-    padding: 6px 10px;
-    background: rgba(0, 0, 0, 0.85);
-    border-radius: 8px;
+    padding: 8px 12px;
+    background: rgba(0, 0, 0, 0.9);
+    border-radius: 12px;
     backdrop-filter: blur(8px);
     z-index: 10;
+    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.5);
   }
 
-  .group {
-    display: flex;
-    gap: 4px;
+  .group { display: flex; gap: 4px; }
+
+  .sep {
+    width: 1px;
+    height: 28px;
+    background: #444;
+    margin: 0 2px;
   }
 
   button {
-    padding: 6px 12px;
+    min-width: 44px;
+    min-height: 44px;
+    padding: 8px 16px;
     border: 1px solid #555;
-    border-radius: 4px;
+    border-radius: 8px;
     background: #333;
     color: #ccc;
     cursor: pointer;
-    font-size: 0.85rem;
+    font-size: 0.9rem;
+    font-weight: 500;
     white-space: nowrap;
+    transition: background 0.15s, border-color 0.15s;
   }
 
-  button:hover:not(:disabled) { background: #555; }
-  button:disabled { opacity: 0.4; cursor: default; }
+  button:hover:not(:disabled) { background: #4a4a4a; }
+
+  button:active:not(:disabled) {
+    background: #555;
+    transform: scale(0.97);
+  }
+
+  button:disabled {
+    opacity: 0.35;
+    cursor: default;
+  }
 
   button.active {
-    background: #4a6;
-    border-color: #4a6;
+    background: #2d7a47;
+    border-color: #3a9e5c;
     color: #fff;
   }
 
   .clear-btn:hover:not(:disabled) {
-    background: #a33;
+    background: #8b2222;
     border-color: #a33;
   }
 
   .submit-btn {
+    min-width: 80px;
     background: #2563eb;
-    border-color: #2563eb;
+    border-color: #3b82f6;
     color: #fff;
-    font-weight: bold;
+    font-weight: 700;
+    font-size: 0.95rem;
   }
 
   .submit-btn:hover:not(:disabled) { background: #1d4ed8; }
+
+  @media (max-width: 600px) {
+    .toolbar {
+      bottom: 72px;
+      padding: 6px 8px;
+      gap: 4px;
+    }
+    button {
+      min-width: 40px;
+      padding: 8px 10px;
+      font-size: 0.8rem;
+    }
+  }
 </style>

src/lib/canvas-storage.js

@@ -1,4 +1,4 @@
-import { getRedis } from './redis-client.js';
+import { getRedis, redisRaw } from './redis-client.js';
 import { CANVAS_WIDTH, TOTAL_PIXELS, BITS_PER_PIXEL, REDIS_CANVAS_KEY } from './constants.js';
 
 /** Total bytes needed for the canvas bitfield */
@@ -53,12 +53,12 @@ export async function getFullCanvas(env) {
  */
 export async function setPixels(env, pixels) {
   if (!pixels.length) return;
-  const redis = getRedis(env);
 
-  let chain = redis.bitfield(REDIS_CANVAS_KEY);
+  // Use raw REST API for BITFIELD — SDK builder API is broken in @upstash/redis 1.x
+  const command = ['BITFIELD', REDIS_CANVAS_KEY];
   for (const { x, y, color } of pixels) {
     const offset = y * CANVAS_WIDTH + x;
-    chain = chain.set('u5', `#${offset}`, color);
+    command.push('SET', 'u5', `#${offset}`, String(color));
   }
-  await chain.exec();
+  await redisRaw(env, command);
 }

src/lib/redis-client.js

@@ -11,3 +11,25 @@ export function getRedis(env) {
     token: env.UPSTASH_REDIS_REST_TOKEN,
   });
 }
+
+/**
+ * Execute a raw Redis command via Upstash REST API.
+ * Useful for commands where the SDK API is unreliable (e.g., BITFIELD).
+ * @param {object} env
+ * @param {string[]} command - Redis command as array, e.g. ['BITFIELD', 'key', 'SET', ...]
+ */
+export async function redisRaw(env, command) {
+  const res = await fetch(env.UPSTASH_REDIS_REST_URL, {
+    method: 'POST',
+    headers: {
+      Authorization: `Bearer ${env.UPSTASH_REDIS_REST_TOKEN}`,
+      'Content-Type': 'application/json',
+    },
+    body: JSON.stringify(command),
+  });
+  if (!res.ok) {
+    const text = await res.text();
+    throw new Error(`Redis command failed: ${res.status} ${text}`);
+  }
+  return res.json();
+}

src/worker.js

@@ -60,10 +60,14 @@ app.post('/api/place', async (c) => {
     return c.json({ error: 'rate_limited', remaining, retryAfter }, 429);
   }
 
-  // Write pixels to canvas
-  await setPixels(c.env, pixels);
+  // Write pixels to canvas + broadcast
+  try {
+    await setPixels(c.env, pixels);
+  } catch (err) {
+    console.error('Redis write failed:', err);
+    return c.json({ error: 'storage_failed', message: String(err) }, 500);
+  }
 
-  // Broadcast to all connected WebSocket clients (non-blocking)
   try {
     const roomId = c.env.CANVAS_ROOM.idFromName('main');
     const room = c.env.CANVAS_ROOM.get(roomId);