feat: Add Manage page, light/dark theme toggle, and URL sharing

- Move Save, Load, Export, Import buttons to a dedicated Manage page
- Add light theme with warm parchment palette; auto-detect via prefers-color-scheme, persisted to localStorage
- Add URL sharing: sheet state is deflate-raw compressed, base64-encoded, and stored in ?c= parameter; auto-save is suppressed when viewing a shared URL
- Extract JS to fabula-ultima-sheet.js

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

fabula-ultima-sheet.css

@@ -964,6 +964,55 @@ input[type="number"] {
   font-weight: 600;
 }
 
+/* ── URL BANNER ──────────────────────────────────── */
+.url-banner {
+  background: var(--surface2);
+  border-bottom: 1px solid var(--teal-dim);
+  padding: 10px 32px;
+  font-family: var(--font-body);
+  font-size: 0.9rem;
+  color: var(--text-dim);
+  display: flex;
+  align-items: center;
+  gap: 10px;
+}
+
+.url-banner strong {
+  color: var(--text);
+}
+
+.url-banner-icon {
+  color: var(--teal);
+  font-size: 0.85rem;
+  flex-shrink: 0;
+}
+
+/* ── MANAGE PAGE ─────────────────────────────────── */
+.manage-grid {
+  display: grid;
+  grid-template-columns: 1fr 1fr;
+  gap: 20px;
+  max-width: 800px;
+}
+
+.manage-desc {
+  font-size: 0.9rem;
+  color: var(--text-dim);
+  line-height: 1.6;
+  margin-bottom: 18px;
+}
+
+.manage-btn-row {
+  display: flex;
+  gap: 10px;
+  flex-wrap: wrap;
+}
+
+.btn-lg {
+  font-size: 0.6rem;
+  padding: 11px 22px;
+}
+
 /* ── LIGHT THEME ─────────────────────────────────── */
 [data-theme="light"] {
   --bg: #f4efe4;

fabula-ultima-sheet.html

@@ -20,21 +20,20 @@
       <button class="tab active" onclick="switchTab('main')">Character</button>
       <button class="tab" onclick="switchTab('classes')">Classes</button>
       <button class="tab" onclick="switchTab('spells')">Arcana & Spells</button>
+      <button class="tab" onclick="switchTab('manage')">Manage</button>
     </div>
     <div class="toolbar">
-      <button class="btn-save" onclick="saveSheet()">✦ Save</button>
-      <button class="btn-load" onclick="loadSheet()">↑ Load</button>
-      <div class="toolbar-sep"></div>
-      <button class="btn-save btn-export" onclick="exportSheet()">↓ Export JSON</button>
-      <button class="btn-load btn-import" onclick="importSheet()">↑ Import JSON</button>
-      <input type="file" id="importFileInput" accept=".json,application/json" style="display:none"
-        onchange="handleImportFile(this)">
       <span class="save-status" id="saveStatus">Saved!</span>
-      <div class="toolbar-sep"></div>
       <button class="btn-theme" id="themeToggle" onclick="toggleTheme()">☀ Light</button>
     </div>
   </header>
 
+  <div id="urlBanner" class="url-banner" style="display:none">
+    <span class="url-banner-icon">⚑</span>
+    Viewing a shared character — auto-save is disabled.
+    Use <strong>Manage → Save to Browser</strong> to keep any changes.
+  </div>
+
   <!-- ══════════════════════════════════════════════════
      PAGE 1: MAIN CHARACTER
 ══════════════════════════════════════════════════ -->
@@ -430,6 +429,44 @@
 
   </div>
 
+  <!-- ══════════════════════════════════════════════════
+     PAGE 4: MANAGE
+══════════════════════════════════════════════════ -->
+  <div class="page" id="page-manage">
+    <div class="manage-grid">
+
+      <div class="section">
+        <div class="section-title"><span class="icon">◈</span> Local Save</div>
+        <p class="manage-desc">Save your character sheet to your browser's local storage, or load a previously saved sheet.</p>
+        <div class="manage-btn-row">
+          <button class="btn-save btn-lg" onclick="saveSheet()">✦ Save to Browser</button>
+          <button class="btn-load btn-lg" onclick="loadSheet()">↑ Load from Browser</button>
+        </div>
+      </div>
+
+      <div class="section">
+        <div class="section-title"><span class="icon">⊕</span> JSON File</div>
+        <p class="manage-desc">Export your character to a JSON file for backup or sharing, or import from a previously exported file.</p>
+        <div class="manage-btn-row">
+          <button class="btn-save btn-export btn-lg" onclick="exportSheet()">↓ Export JSON</button>
+          <button class="btn-load btn-import btn-lg" onclick="importSheet()">↑ Import JSON</button>
+          <input type="file" id="importFileInput" accept=".json,application/json" style="display:none"
+            onchange="handleImportFile(this)">
+        </div>
+      </div>
+
+      <div class="section col-span-2">
+        <div class="section-title"><span class="icon">⎘</span> Share via URL</div>
+        <p class="manage-desc">Encode your character's current state into a shareable link. Anyone who opens the link will see your character — auto-save is disabled for viewers.</p>
+        <div class="manage-btn-row">
+          <button class="btn-save btn-export btn-lg" onclick="copyShareURL()">⎘ Copy URL</button>
+          <span class="save-status" id="copyStatus">Copied!</span>
+        </div>
+      </div>
+
+    </div>
+  </div>
+
   <script src="fabula-ultima-sheet.js"></script>
 </body>
 

fabula-ultima-sheet.js

@@ -1,4 +1,5 @@
 // ── STATE ──────────────────────────────────────────
+let urlMode = false;
 let level = 1;
 let fpCount = 0;
 let primaryClasses = [];
@@ -25,7 +26,7 @@ function switchTab(tab) {
 }
 
 // ── INIT ───────────────────────────────────────────
-function init() {
+async function init() {
   const savedTheme = localStorage.getItem('fabulaUltimaTheme')
     || (window.matchMedia('(prefers-color-scheme: light)').matches ? 'light' : 'dark');
   document.getElementById('themeToggle').textContent = savedTheme === 'light' ? '☾ Dark' : '☀ Light';
@@ -36,7 +37,50 @@ function init() {
   renderOtherClasses();
   renderSpells();
   updateXPBar();
-  tryAutoLoad();
+  if (!await tryLoadFromURL()) tryAutoLoad();
+}
+
+// ── URL STATE ──────────────────────────────────────
+async function compressToBase64(str) {
+  const stream = new CompressionStream('deflate-raw');
+  const writer = stream.writable.getWriter();
+  writer.write(new TextEncoder().encode(str));
+  writer.close();
+  const buf = await new Response(stream.readable).arrayBuffer();
+  const bytes = new Uint8Array(buf);
+  let binary = '';
+  for (let i = 0; i < bytes.length; i++) binary += String.fromCharCode(bytes[i]);
+  return btoa(binary);
+}
+
+async function decompressFromBase64(b64) {
+  try {
+    const bytes = Uint8Array.from(atob(b64), c => c.charCodeAt(0));
+    const stream = new DecompressionStream('deflate-raw');
+    const writer = stream.writable.getWriter();
+    writer.write(bytes);
+    writer.close();
+    const buf = await new Response(stream.readable).arrayBuffer();
+    return new TextDecoder().decode(buf);
+  } catch {
+    // Fall back to legacy uncompressed URLs
+    return decodeURIComponent(escape(atob(b64)));
+  }
+}
+
+async function tryLoadFromURL() {
+  const encoded = new URLSearchParams(window.location.search).get('c');
+  if (!encoded) return false;
+  try {
+    const json = await decompressFromBase64(encoded);
+    applyData(JSON.parse(json));
+    urlMode = true;
+    document.getElementById('urlBanner').style.display = 'block';
+    return true;
+  } catch (e) {
+    console.warn('Could not load state from URL:', e);
+    return false;
+  }
 }
 
 // ── STATUS EFFECTS ─────────────────────────────────
@@ -236,7 +280,8 @@ function collectData() {
   };
 }
 
-function saveSheet() {
+function saveSheet(isAuto = false) {
+  if (isAuto && urlMode) return;
   const data = collectData();
   localStorage.setItem('fabulaUltimaSheet', JSON.stringify(data));
   const st = document.getElementById('saveStatus');
@@ -350,6 +395,16 @@ function handleImportFile(input) {
   reader.readAsText(file);
 }
 
+async function copyShareURL() {
+  const json = JSON.stringify(collectData());
+  const encoded = await compressToBase64(json);
+  const url = window.location.origin + window.location.pathname + '?c=' + encodeURIComponent(encoded);
+  await navigator.clipboard.writeText(url);
+  const st = document.getElementById('copyStatus');
+  st.classList.add('show');
+  setTimeout(() => st.classList.remove('show'), 2000);
+}
+
 // ── THEME ──────────────────────────────────────────
 function toggleTheme() {
   const html = document.documentElement;
@@ -360,6 +415,6 @@ function toggleTheme() {
 }
 
 // Auto-save every 30s
-setInterval(saveSheet, 30000);
+setInterval(() => saveSheet(true), 30000);
 
 init();