diff --git a/CLAUDE.md b/CLAUDE.md
index 2a734b4..adf89f5 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -127,12 +127,82 @@ http://localhost:3300/tasks/{type}/editor.html?file={docId}
 4. Server computes diff → writes `temp/{docId}.diff.json`
 5. Server runs `generate.mjs` → regenerates output.html + screenshots
 
+**Browser-sync reload protection:** Editor pages are not reloaded when `output.html` changes (removed from watch list). The server also deduplicates rapid-fire save requests (browser-sync quirk: may relay POSTs twice).
+
 **Claude reviewing editor changes:**
 ```bash
 cat tasks/{type}/temp/{docId}.diff.json           # see what changed
 # Read screenshot PNGs from tasks/{type}/temp/{docId}-page-{N}.png to verify visually
 ```
 
+### Building a New Editor
+
+Reference implementation: `tasks/asteroid-splitting/editor.html` (simplest, cleanest pattern).
+
+**1. HTML scaffold** — copy toolbar/statusbar/container from asteroid-splitting editor:
+- `#toolbar` with btn-prev, btn-next, btn-reset, btn-copy, btn-copy-changes, btn-save
+- `#worksheet-container` (EditorCore fills this)
+- `#statusbar`, `#toast`, `#coord-tooltip`
+- CSS for `.editor-selected`, `.editor-changed`, toolbar, page labels
+
+**2. Load editor-core.js:**
+```html
+<script src="../../src/editor/editor-core.js"></script>
+```
+
+**3. Initialize EditorCore** (wrap everything in IIFE):
+```javascript
+(function() {
+  'use strict';
+  const core = EditorCore.init({
+    taskType: 'your-type-name',
+    serialize: buildConfig,        // required: (changesOnly) => data object
+    onReset: resetCurrentPage,     // optional: (pageNum) => void
+    onReady(pages, mmToPx) {       // setup DOM refs, event handlers
+      findElements(pages);
+      setupClickHandlers();
+      setupKeyboard();
+    },
+    onDataLoaded(data) {           // apply saved data.json to DOM
+      if (data) applyData(data);
+    }
+  });
+  // ... function implementations
+})();
+```
+
+**4. State management pattern:**
+- Store original element state in a `Map` on init (for change detection + reset)
+- Track in-memory references to editable elements in arrays
+- Read current state from DOM when serializing
+- Use `markChanged(el)` to toggle `.editor-changed` class by comparing to original
+
+**5. Serialization:**
+- `buildConfig(changesOnly)` returns `{ pages: [{ page: N, ...task-specific fields }] }`
+- When `changesOnly=true`, skip elements matching original state
+- EditorCore calls this for Save and Copy
+
+**6. Do NOT:**
+- Use synchronous XHR (use EditorCore's async save)
+- Bypass EditorCore's save (no manual fetch to `/api/save-edits`)
+- Add duplicate event listeners for Save/Copy buttons (core wires them)
+- Use `var` (use `const`/`let`)
+- Store state only in DOM without in-memory backup
+
+**7. Element identification in templates:**
+- For complex/reorderable elements: use `data-*` attributes (see space-route `data-node-id`)
+- For simple sequential elements: index-based matching is fine
+- Match the strategy in your `generate.mjs`
+
+**8. Mandatory e2e verification** (use Chrome DevTools MCP):
+1. Open editor → verify worksheet loads and sections are found
+2. Click element → verify selection highlight and status info
+3. Modify via keyboard → verify DOM and info update
+4. Click Save → verify toast "Saved!" and no page reload
+5. Read `data.json` → verify saved values match editor state
+6. Run `generate.mjs` → verify transforms in `output.html`
+7. Reload editor → verify saved state restored via `onDataLoaded`
+
 ## Preview Pages Structure
 
 Three-level navigation hierarchy, maintained manually by Claude:
diff --git a/bs-config.cjs b/bs-config.cjs
index 944aedc..7552e52 100644
--- a/bs-config.cjs
+++ b/bs-config.cjs
@@ -2,6 +2,9 @@ const fs = require('fs');
 const path = require('path');
 const { execFile } = require('child_process');
 
+// Deduplicate rapid-fire save requests (browser-sync may relay POSTs twice)
+const _lastSave = {};
+
 module.exports = {
   server: {
     baseDir: "."
@@ -10,7 +13,7 @@ module.exports = {
     "tasks/index.html",
     "tasks/*/index.html",
     "tasks/*/docs/*.template.html",
-    "tasks/*/docs/*.output.html",
+    // output.html excluded: generated by save flow, reload would wipe editor state
     "tasks/*/editor.html",
     "assets/**/*",
     "public/**/*"
@@ -48,6 +51,17 @@ module.exports = {
               return;
             }
 
+            // Deduplicate: skip if same docId saved within 500ms
+            const saveKey = `${taskType}/${docId}`;
+            const now = Date.now();
+            if (_lastSave[saveKey] && now - _lastSave[saveKey].time < 500) {
+              console.log(`[save] dedup skip ${saveKey} (${now - _lastSave[saveKey].time}ms since last)`);
+              res.writeHead(200, { 'Content-Type': 'application/json' });
+              res.end(JSON.stringify({ ok: true, dedup: true }));
+              return;
+            }
+            _lastSave[saveKey] = { time: now, body: body.length };
+
             const docsDir = path.join(__dirname, 'tasks', taskType, 'docs');
             const tempDir = path.join(__dirname, 'tasks', taskType, 'temp');
             fs.mkdirSync(tempDir, { recursive: true });
diff --git a/output/pdf/asteroid-splitting-1.pdf b/output/pdf/asteroid-splitting-1.pdf
new file mode 100644
index 0000000..6450cd7
Binary files /dev/null and b/output/pdf/asteroid-splitting-1.pdf differ
diff --git a/src/editor/editor-core.js b/src/editor/editor-core.js
index cd0c0aa..d6a5ddd 100644
--- a/src/editor/editor-core.js
+++ b/src/editor/editor-core.js
@@ -59,8 +59,8 @@ window.EditorCore = (function () {
       _wireButton('btn-reset', () => opts.onReset(_currentPage + 1));
     }
 
-    // Load worksheet
-    _loadWorksheet(_config.filePath, opts.onReady);
+    // Load worksheet, then optionally load data.json
+    _loadWorksheet(_config.filePath, opts.onReady, opts.onDataLoaded);
 
     return {
       get pages() { return _pages; },
@@ -72,12 +72,13 @@ window.EditorCore = (function () {
       showTooltip,
       hideTooltip,
       setSerializer: (fn) => { _serializeFn = fn; },
+      loadData: () => _loadDataJson(_config.fileParam),
     };
   }
 
   // ---- Worksheet Loading ----
 
-  function _loadWorksheet(filePath, onReady) {
+  function _loadWorksheet(filePath, onReady, onDataLoaded) {
     fetch(filePath)
       .then(r => { if (!r.ok) throw new Error(r.status); return r.text(); })
       .then(html => {
@@ -111,6 +112,12 @@ window.EditorCore = (function () {
         setTimeout(() => {
           _initPages();
           if (onReady) onReady(_pages, _mmToPx);
+          // Load data.json after onReady so DOM references are set up
+          if (onDataLoaded) {
+            _loadDataJson(_config.fileParam).then(data => {
+              onDataLoaded(data, _pages, _mmToPx);
+            });
+          }
         }, 350);
       })
       .catch(err => {
@@ -119,6 +126,16 @@ window.EditorCore = (function () {
       });
   }
 
+  async function _loadDataJson(docId) {
+    try {
+      const resp = await fetch('docs/' + docId + '.data.json');
+      if (!resp.ok) return null;
+      return await resp.json();
+    } catch (e) {
+      return null;
+    }
+  }
+
   // ---- Pages ----
 
   function _initPages() {
diff --git a/src/scripts/generate-pdf.mjs b/src/scripts/generate-pdf.mjs
index 0e89d81..1b40028 100644
--- a/src/scripts/generate-pdf.mjs
+++ b/src/scripts/generate-pdf.mjs
@@ -1,9 +1,20 @@
 import puppeteer from 'puppeteer';
-import { resolve, basename } from 'path';
+import { resolve, basename, dirname } from 'path';
 import { existsSync, mkdirSync } from 'fs';
 import { fileURLToPath } from 'url';
+import { createServer } from 'http';
+import { readFile } from 'fs/promises';
+import { extname } from 'path';
 
-const OUTPUT_DIR = resolve(fileURLToPath(import.meta.url), '../../../output/pdf');
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const PROJECT_ROOT = resolve(__dirname, '../..');
+const OUTPUT_DIR = resolve(PROJECT_ROOT, 'output/pdf');
+
+const MIME_TYPES = {
+  '.html': 'text/html', '.css': 'text/css', '.js': 'application/javascript',
+  '.png': 'image/png', '.jpg': 'image/jpeg', '.jpeg': 'image/jpeg',
+  '.webp': 'image/webp', '.svg': 'image/svg+xml', '.json': 'application/json',
+};
 
 async function generatePdf(htmlPath) {
   const absolutePath = resolve(htmlPath);
@@ -14,13 +25,33 @@ async function generatePdf(htmlPath) {
 
   mkdirSync(OUTPUT_DIR, { recursive: true });
 
-  const pdfName = basename(absolutePath, '.html') + '.pdf';
+  // Strip .output and .template from PDF filename
+  let pdfName = basename(absolutePath, '.html');
+  pdfName = pdfName.replace(/\.(output|template)$/, '') + '.pdf';
   const pdfPath = resolve(OUTPUT_DIR, pdfName);
 
-  const browser = await puppeteer.launch({ headless: true });
+  // Start temp HTTP server to resolve /assets/ paths correctly
+  const server = createServer(async (req, res) => {
+    const filePath = resolve(PROJECT_ROOT, decodeURIComponent(req.url).replace(/^\//, ''));
+    try {
+      const data = await readFile(filePath);
+      const ext = extname(filePath);
+      res.writeHead(200, { 'Content-Type': MIME_TYPES[ext] || 'application/octet-stream' });
+      res.end(data);
+    } catch {
+      res.writeHead(404);
+      res.end('Not found');
+    }
+  });
+
+  await new Promise(r => server.listen(0, '127.0.0.1', r));
+  const port = server.address().port;
+  const relPath = absolutePath.replace(PROJECT_ROOT + '/', '');
+
+  const browser = await puppeteer.launch({ headless: true, args: ['--no-sandbox'] });
   const page = await browser.newPage();
 
-  await page.goto(`file://${absolutePath}`, { waitUntil: 'networkidle0' });
+  await page.goto(`http://127.0.0.1:${port}/${relPath}`, { waitUntil: 'networkidle0', timeout: 30000 });
 
   await page.pdf({
     path: pdfPath,
@@ -31,6 +62,7 @@ async function generatePdf(htmlPath) {
   });
 
   await browser.close();
+  server.close();
   console.log(`PDF generated: ${pdfPath}`);
   return pdfPath;
 }
diff --git a/tasks/asteroid-splitting/CLAUDE.md b/tasks/asteroid-splitting/CLAUDE.md
index 9c19a70..d0f281d 100644
--- a/tasks/asteroid-splitting/CLAUDE.md
+++ b/tasks/asteroid-splitting/CLAUDE.md
@@ -124,11 +124,10 @@ The editor adjusts the **scale and rotation** of asteroid images in each section
 
 ### Data flow
 
-- Editor reads `.template.html` (via EditorCore)
-- On load, fetches `.data.json` and applies transforms to DOM (`img.style.transform`)
-- On Save, reads transforms FROM DOM → sync XHR POST → server writes `.data.json`
+- Editor reads `.template.html` (via EditorCore) and `.data.json` (via `onDataLoaded`)
+- On load, applies saved transforms to DOM (`img.style.transform`)
+- Original transforms stored in Map for change detection and reset
+- On Save, serializes transforms from DOM → async POST via EditorCore → server writes `.data.json`
 - `generate.mjs` reads `.data.json`, applies `style="transform: ..."` to img elements in `.output.html`
 
-### Status: BROKEN
-
-The editor has a reliability problem with the save cycle. The server's save endpoint runs `generate.mjs` asynchronously after writing `data.json`. `generate.mjs` writes `.output.html`, which triggers browser-sync live-reload. The reload can interfere with the save flow, causing data loss or incomplete saves. This needs to be investigated and fixed before the editor can be used reliably.
+This editor serves as the **reference implementation** for building new task-type editors (see root CLAUDE.md "Building a New Editor").
diff --git a/tasks/asteroid-splitting/docs/asteroid-splitting-1.data.json b/tasks/asteroid-splitting/docs/asteroid-splitting-1.data.json
index 1095e44..0b3f48a 100644
--- a/tasks/asteroid-splitting/docs/asteroid-splitting-1.data.json
+++ b/tasks/asteroid-splitting/docs/asteroid-splitting-1.data.json
@@ -65,8 +65,8 @@
       "sections": [
         {
           "index": 0,
-          "scale": 1,
-          "rotate": 0
+          "scale": 1.2,
+          "rotate": 10
         },
         {
           "index": 1,
@@ -150,8 +150,8 @@
         },
         {
           "index": 1,
-          "scale": 1,
-          "rotate": 0
+          "scale": 2,
+          "rotate": 30
         },
         {
           "index": 2,
@@ -165,8 +165,8 @@
       "sections": [
         {
           "index": 0,
-          "scale": 1,
-          "rotate": 0
+          "scale": 2,
+          "rotate": 30
         },
         {
           "index": 1,
diff --git a/tasks/asteroid-splitting/editor.html b/tasks/asteroid-splitting/editor.html
index a0da146..e3f1f32 100644
--- a/tasks/asteroid-splitting/editor.html
+++ b/tasks/asteroid-splitting/editor.html
@@ -19,7 +19,6 @@
     #toolbar button:hover { background: #0f3460; }
     #toolbar button.primary { background: #533483; border-color: #7b2d8e; }
     #toolbar button.save { background: #1b8a5a; border-color: #239b6e; }
-    #toolbar button[disabled] { opacity: 0.4; cursor: not-allowed; }
     #page-indicator { color: #a0a0c0; font-weight: 600; min-width: 100px; text-align: center; }
     .spacer { flex: 1; }
     #statusbar {
@@ -37,6 +36,7 @@
       padding: 2px 12px; border-radius: 4px;
     }
     .editor-selected { outline: 3px solid #7c3aed !important; outline-offset: 4px; }
+    .editor-changed { position: relative; }
     .editor-changed::after {
       content: ''; position: absolute; top: -2px; right: -2px;
       width: 8px; height: 8px; background: #f97316; border-radius: 50%; z-index: 10;
@@ -63,8 +63,10 @@
   <div class="spacer"></div>
   <span id="selection-info" style="color: #c4b5fd; font-size: 12px;">Loading...</span>
   <div class="spacer"></div>
+  <button id="btn-reset">Reset Page</button>
   <button id="btn-copy" class="primary">Copy JSON</button>
-  <button id="btn-save" class="save" disabled>Save</button>
+  <button id="btn-copy-changes" class="primary">Copy Changes</button>
+  <button id="btn-save" class="save">Save</button>
 </div>
 <div id="worksheet-container"></div>
 <div id="statusbar">
@@ -75,21 +77,19 @@
 
 <script src="../../src/editor/editor-core.js"></script>
 <script>
-  // ============================================================
-  //  Simple approach: ALL state lives in the DOM (img.style.transform).
-  //  No in-memory state. buildConfig reads from DOM.
-  //  Like collecting-asteroids editor pattern.
-  // ============================================================
+(function() {
+  'use strict';
 
-  var sectionEls = []; // [{container, bigImg, smallImgs, pageNum, secIndex}]
-  var selected = null; // currently selected section
-  var ready = false;
+  const sectionEls = [];              // [{container, bigImg, smallImgs, pageNum, secIndex}]
+  const originalTransforms = new Map(); // "pageNum-secIndex" → {scale, rotate}
+  let selected = null;
+
+  // --- Transform helpers ---
 
-  // --- Parse transform string from DOM ---
   function parseTransform(img) {
-    var t = img.style.transform || '';
-    var sm = t.match(/scale\(([\d.]+)\)/);
-    var rm = t.match(/rotate\(([-\d.]+)deg\)/);
+    const t = img.style.transform || '';
+    const sm = t.match(/scale\(([\d.]+)\)/);
+    const rm = t.match(/rotate\(([-\d.]+)deg\)/);
     return {
       scale: sm ? parseFloat(sm[1]) : 1,
       rotate: rm ? parseFloat(rm[1]) : 0
@@ -97,29 +97,42 @@
   }
 
   function setTransform(img, scale, rotate) {
-    img.style.transform = 'scale(' + scale + ') rotate(' + rotate + 'deg)';
+    if (scale === 1 && rotate === 0) {
+      img.style.transform = '';
+    } else {
+      img.style.transform = 'scale(' + scale + ') rotate(' + rotate + 'deg)';
+    }
+  }
+
+  function secKey(sec) {
+    return sec.pageNum + '-' + sec.secIndex;
   }
 
   // --- Find all sections in loaded pages ---
+
   function findSections(pages) {
-    sectionEls = [];
+    sectionEls.length = 0;
     pages.forEach(function(page, pi) {
-      var glows = page.querySelectorAll('.asteroid-glow');
+      const glows = page.querySelectorAll('.asteroid-glow');
       glows.forEach(function(container, si) {
-        var bigImg = container.querySelector('img');
-        var sectionRow = container.parentElement;
+        const bigImg = container.querySelector('img');
+        // Walk up to find the section row containing formula small imgs
+        let sectionRow = container.parentElement;
         while (sectionRow && !sectionRow.classList.contains('gap-[8mm]')) {
           sectionRow = sectionRow.parentElement;
         }
         if (!sectionRow) sectionRow = container.parentElement;
 
-        var allImgs = sectionRow.querySelectorAll('img[src*="pack3-asteroids"]');
-        var smallImgs = [];
+        const allImgs = sectionRow.querySelectorAll('img[src*="pack3-asteroids"]');
+        const smallImgs = [];
         allImgs.forEach(function(img) { if (img !== bigImg) smallImgs.push(img); });
 
-        var sec = { container: container, bigImg: bigImg, smallImgs: smallImgs, pageNum: pi + 1, secIndex: si };
+        const sec = { container, bigImg, smallImgs, pageNum: pi + 1, secIndex: si };
         sectionEls.push(sec);
 
+        // Store original transform (from template, before data.json applied)
+        originalTransforms.set(secKey(sec), { scale: 1, rotate: 0 });
+
         container.style.cursor = 'pointer';
         container.addEventListener('click', function(e) {
           e.stopPropagation();
@@ -127,94 +140,124 @@
         });
       });
     });
+
+    document.getElementById('status-text').textContent =
+      sectionEls.length + ' sections. Keys: +/- scale \u2022 [/] rotate (Shift=fine) \u2022 0 reset';
+    document.getElementById('selection-info').textContent = 'Click a big asteroid to select';
   }
 
+  // --- Selection ---
+
   function selectSection(sec) {
-    if (selected) selected.container.classList.remove('editor-selected');
+    deselectAll();
     selected = sec;
     sec.container.classList.add('editor-selected');
-    showInfo();
+    updateInfo();
   }
 
-  function showInfo() {
-    var el = document.getElementById('selection-info');
+  function deselectAll() {
+    if (selected) {
+      selected.container.classList.remove('editor-selected');
+      selected = null;
+    }
+    updateInfo();
+  }
+
+  function updateInfo() {
+    const el = document.getElementById('selection-info');
     if (!selected) { el.textContent = 'Click a big asteroid to select'; return; }
-    var t = parseTransform(selected.bigImg);
+    const t = parseTransform(selected.bigImg);
     el.textContent = 'Page ' + selected.pageNum + ' Sec ' + (selected.secIndex + 1) +
-      ' \u2014 scale: ' + t.scale.toFixed(2) + ' rotate: ' + t.rotate + '\u00B0';
+      ' \u2014 scale: ' + t.scale.toFixed(2) + ' rotate: ' + t.rotate.toFixed(1) + '\u00B0';
   }
 
-  // --- Apply scale/rotate to big + all small imgs ---
+  // --- Apply transform to section (big + small imgs) ---
+
   function applyToSection(sec, scale, rotate) {
     setTransform(sec.bigImg, scale, rotate);
     sec.smallImgs.forEach(function(img) { setTransform(img, scale, rotate); });
-    sec.container.classList.toggle('editor-changed', scale !== 1 || rotate !== 0);
-    showInfo();
+    markChanged(sec);
+    updateInfo();
   }
 
-  // --- Load data.json and apply transforms to DOM ---
-  function loadData(docId, cb) {
-    var xhr = new XMLHttpRequest();
-    xhr.open('GET', 'docs/' + docId + '.data.json', true);
-    xhr.onload = function() {
-      if (xhr.status === 200) {
-        try {
-          var data = JSON.parse(xhr.responseText);
-          var n = 0;
-          (data.pages || []).forEach(function(p) {
-            (p.sections || []).forEach(function(s) {
-              if (s.scale === 1 && s.rotate === 0) return;
-              var sec = sectionEls.find(function(el) {
-                return el.pageNum === p.page && el.secIndex === s.index;
-              });
-              if (sec) { applyToSection(sec, s.scale, s.rotate); n++; }
-            });
-          });
-          if (n > 0) core.showToast('Loaded ' + n + ' edits');
-        } catch(e) {}
-      }
-      if (cb) cb();
-    };
-    xhr.onerror = function() { if (cb) cb(); };
-    xhr.send();
+  // --- Change tracking ---
+
+  function markChanged(sec) {
+    const orig = originalTransforms.get(secKey(sec));
+    const cur = parseTransform(sec.bigImg);
+    const changed = Math.abs(cur.scale - orig.scale) > 0.001 || Math.abs(cur.rotate - orig.rotate) > 0.1;
+    sec.container.classList.toggle('editor-changed', changed);
   }
 
-  // --- Serialize: read ALL transforms from DOM ---
-  function buildConfig() {
-    var pagesMap = {};
+  // --- Apply data.json to DOM (called by EditorCore.onDataLoaded) ---
+
+  function applyData(data) {
+    if (!data || !data.pages) return;
+    let count = 0;
+    data.pages.forEach(function(p) {
+      (p.sections || []).forEach(function(s) {
+        const sec = sectionEls.find(function(el) {
+          return el.pageNum === p.page && el.secIndex === s.index;
+        });
+        if (sec) {
+          const scale = s.scale ?? 1;
+          const rotate = s.rotate ?? 0;
+          applyToSection(sec, scale, rotate);
+          // After applying saved data, update originals so "changed" is relative to saved state
+          originalTransforms.set(secKey(sec), { scale, rotate });
+          sec.container.classList.remove('editor-changed');
+          count++;
+        }
+      });
+    });
+    if (count > 0) core.showToast('Loaded ' + count + ' edits');
+  }
+
+  // --- Serialization ---
+
+  function buildConfig(changesOnly) {
+    const pagesMap = {};
     sectionEls.forEach(function(sec) {
-      var t = parseTransform(sec.bigImg);
+      const cur = parseTransform(sec.bigImg);
+      const orig = originalTransforms.get(secKey(sec));
+
+      if (changesOnly) {
+        const changed = Math.abs(cur.scale - orig.scale) > 0.001 || Math.abs(cur.rotate - orig.rotate) > 0.1;
+        if (!changed) return;
+      }
+
       if (!pagesMap[sec.pageNum]) pagesMap[sec.pageNum] = { page: sec.pageNum, sections: [] };
       pagesMap[sec.pageNum].sections.push({
         index: sec.secIndex,
-        scale: +t.scale.toFixed(3),
-        rotate: +t.rotate.toFixed(1)
+        scale: +cur.scale.toFixed(3),
+        rotate: +cur.rotate.toFixed(1)
       });
     });
     return { pages: Object.values(pagesMap) };
   }
 
-  // --- Save: sync XHR, read from DOM ---
-  function saveToServer() {
-    if (!ready) return;
-    var data = buildConfig();
-    try {
-      var xhr = new XMLHttpRequest();
-      xhr.open('POST', '/api/save-edits', false);
-      xhr.setRequestHeader('Content-Type', 'application/json');
-      xhr.send(JSON.stringify({ taskType: 'asteroid-splitting', docId: core.docId, data: data }));
-      core.showToast(xhr.status === 200 ? 'Saved!' : 'Error: ' + xhr.statusText);
-    } catch(e) {
-      core.showToast('Save failed: ' + e.message);
-    }
+  // --- Reset ---
+
+  function resetCurrentPage(pageNum) {
+    sectionEls.forEach(function(sec) {
+      if (sec.pageNum !== pageNum) return;
+      const orig = originalTransforms.get(secKey(sec));
+      applyToSection(sec, orig.scale, orig.rotate);
+      sec.container.classList.remove('editor-changed');
+    });
+    if (selected && selected.pageNum === pageNum) updateInfo();
   }
 
   // --- Keyboard ---
+
   document.addEventListener('keydown', function(e) {
+    if (e.key === 'Escape') { deselectAll(); return; }
     if (!selected) return;
-    var t = parseTransform(selected.bigImg);
-    var step = e.shiftKey ? 0.01 : 0.05;
-    var rotStep = e.shiftKey ? 1 : 5;
+
+    const t = parseTransform(selected.bigImg);
+    const step = e.shiftKey ? 0.01 : 0.05;
+    const rotStep = e.shiftKey ? 1 : 5;
+
     switch (e.key) {
       case '+': case '=':
         applyToSection(selected, Math.min(2, +(t.scale + step).toFixed(3)), t.rotate);
@@ -223,53 +266,37 @@
         applyToSection(selected, Math.max(0.3, +(t.scale - step).toFixed(3)), t.rotate);
         e.preventDefault(); break;
       case '[':
-        applyToSection(selected, t.scale, t.rotate - rotStep);
+        applyToSection(selected, t.scale, +(t.rotate - rotStep).toFixed(1));
         e.preventDefault(); break;
       case ']':
-        applyToSection(selected, t.scale, t.rotate + rotStep);
+        applyToSection(selected, t.scale, +(t.rotate + rotStep).toFixed(1));
         e.preventDefault(); break;
       case '0':
         applyToSection(selected, 1, 0);
         e.preventDefault(); break;
-      case 'Escape':
-        if (selected) { selected.container.classList.remove('editor-selected'); selected = null; showInfo(); }
-        break;
     }
   });
 
   document.addEventListener('click', function(e) {
     if (selected && !e.target.closest('.asteroid-glow')) {
-      selected.container.classList.remove('editor-selected');
-      selected = null; showInfo();
+      deselectAll();
     }
   });
 
-  // --- Init ---
-  // NOTE: do NOT pass serialize to EditorCore — we handle Save ourselves
-  // to avoid double-handler (EditorCore's async + ours sync) race condition
-  var core = EditorCore.init({
+  // --- Init via EditorCore ---
+
+  const core = EditorCore.init({
     taskType: 'asteroid-splitting',
+    serialize: buildConfig,
+    onReset: resetCurrentPage,
     onReady: function(pages) {
       findSections(pages);
-      document.getElementById('status-text').textContent =
-        sectionEls.length + ' sections. Keys: +/- scale \u2022 [/] rotate (Shift=fine) \u2022 0 reset';
-      // Load saved data, then enable Save
-      loadData(core.docId, function() {
-        ready = true;
-        document.getElementById('btn-save').disabled = false;
-        document.getElementById('selection-info').textContent = 'Click a big asteroid to select';
-      });
-      // Wire Save button directly (EditorCore won't touch it without serialize)
-      document.getElementById('btn-save').addEventListener('click', function(e) {
-        saveToServer();
-      });
-      // Wire Copy JSON
-      document.getElementById('btn-copy').addEventListener('click', function(e) {
-        var json = JSON.stringify(buildConfig(), null, 2);
-        navigator.clipboard.writeText(json).then(function() { core.showToast('Copied!'); });
-      });
+    },
+    onDataLoaded: function(data) {
+      if (data) applyData(data);
     }
   });
+})();
 </script>
 </body>
 </html>