diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
index fc94342..3636a26 100644
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@@ -10,6 +10,8 @@ on:
 jobs:
   build:
     runs-on: ubuntu-latest
+    env:
+      WEB_EXT_IGNORE_FILES: scripts/**
 
     steps:
       - uses: actions/checkout@v4
diff --git a/importExport.js b/importExport.js
index 3e55fca..dff6cb4 100644
--- a/importExport.js
+++ b/importExport.js
@@ -1,5 +1,55 @@
 // Import/Export functionality for Video Speed Controller settings
 
+const EXPORTABLE_LOCAL_SETTINGS_KEYS = ["customButtonIcons"];
+
+function getExportableLocalSettings(localStorage) {
+  const exportable = {};
+  const customButtonIcons =
+    localStorage &&
+    localStorage.customButtonIcons &&
+    typeof localStorage.customButtonIcons === "object" &&
+    !Array.isArray(localStorage.customButtonIcons)
+      ? localStorage.customButtonIcons
+      : null;
+
+  if (customButtonIcons) {
+    exportable.customButtonIcons = customButtonIcons;
+  }
+
+  return exportable;
+}
+
+function replaceImportableLocalSettings(localSettings, callback) {
+  chrome.storage.local.remove(EXPORTABLE_LOCAL_SETTINGS_KEYS, function () {
+    if (chrome.runtime.lastError) {
+      showStatus(
+        "Error: Failed to clear local icon overrides - " +
+          chrome.runtime.lastError.message,
+        true
+      );
+      return;
+    }
+
+    if (!localSettings || Object.keys(localSettings).length === 0) {
+      callback();
+      return;
+    }
+
+    chrome.storage.local.set(localSettings, function () {
+      if (chrome.runtime.lastError) {
+        showStatus(
+          "Error: Failed to save local icon overrides - " +
+            chrome.runtime.lastError.message,
+          true
+        );
+        return;
+      }
+
+      callback();
+    });
+  });
+}
+
 function generateBackupFilename() {
   const now = new Date();
   const year = now.getFullYear();
@@ -11,30 +61,69 @@ function generateBackupFilename() {
   return `speeder-backup_${year}-${month}-${day}_${hours}.${minutes}.${seconds}.json`;
 }
 
+function getBackupManifestVersion() {
+  var manifest = chrome.runtime.getManifest();
+  return manifest && manifest.version ? manifest.version : "unknown";
+}
+
+function getExportableSyncSettings(syncStorage) {
+  return vscBuildStoredSettingsDiff(vscExpandStoredSettings(syncStorage));
+}
+
+function getImportableSyncSettings(backup, rawSettings) {
+  var importable = vscClonePlainData(rawSettings) || {};
+
+  if (
+    backup &&
+    backup.siteRulesFormat &&
+    importable.siteRulesFormat === undefined
+  ) {
+    importable.siteRulesFormat = backup.siteRulesFormat;
+  }
+
+  if (
+    backup &&
+    backup.siteRulesMeta &&
+    importable.siteRulesMeta === undefined
+  ) {
+    importable.siteRulesMeta = backup.siteRulesMeta;
+  }
+
+  return vscExpandStoredSettings(importable);
+}
+
 function exportSettings() {
   chrome.storage.sync.get(null, function (storage) {
-    chrome.storage.local.get(null, function (localStorage) {
-      const backup = {
-        version: "1.1",
-        exportDate: new Date().toISOString(),
-        settings: storage,
-        localSettings: localStorage || {}
-      };
+    chrome.storage.local.get(
+      EXPORTABLE_LOCAL_SETTINGS_KEYS,
+      function (localStorage) {
+        const localSettings = getExportableLocalSettings(localStorage);
+        const syncSettings = getExportableSyncSettings(storage);
+        const backup = {
+          version: getBackupManifestVersion(),
+          exportDate: new Date().toISOString(),
+          settings: syncSettings
+        };
 
-      const dataStr = JSON.stringify(backup, null, 2);
-      const blob = new Blob([dataStr], { type: "application/json" });
-      const url = URL.createObjectURL(blob);
+        if (Object.keys(localSettings).length > 0) {
+          backup.localSettings = localSettings;
+        }
 
-      const link = document.createElement("a");
-      link.href = url;
-      link.download = generateBackupFilename();
-      document.body.appendChild(link);
-      link.click();
-      document.body.removeChild(link);
-      URL.revokeObjectURL(url);
+        const dataStr = JSON.stringify(backup, null, 2);
+        const blob = new Blob([dataStr], { type: "application/json" });
+        const url = URL.createObjectURL(blob);
 
-      showStatus("Settings exported successfully");
-    });
+        const link = document.createElement("a");
+        link.href = url;
+        link.download = generateBackupFilename();
+        document.body.appendChild(link);
+        link.click();
+        document.body.removeChild(link);
+        URL.revokeObjectURL(url);
+
+        showStatus("Settings exported successfully");
+      }
+    );
   });
 }
 
@@ -55,9 +144,9 @@ function importSettings() {
 
         // Detect backup format: check for 'settings' wrapper or raw storage keys
         if (backup.settings && typeof backup.settings === "object") {
-          settingsToImport = backup.settings;
+          settingsToImport = getImportableSyncSettings(backup, backup.settings);
         } else if (typeof backup === "object" && (backup.keyBindings || backup.rememberSpeed !== undefined)) {
-          settingsToImport = backup; // Raw storage object
+          settingsToImport = getImportableSyncSettings(backup, backup);
         }
 
         if (!settingsToImport) {
@@ -65,49 +154,29 @@ function importSettings() {
           return;
         }
 
-        var localToImport =
-          backup.localSettings && typeof backup.localSettings === "object"
-            ? backup.localSettings
-            : null;
+        var localToImport = getExportableLocalSettings(backup.localSettings);
 
         function afterLocalImport() {
-          chrome.storage.sync.clear(function () {
-            chrome.storage.sync.set(settingsToImport, function () {
-              if (chrome.runtime.lastError) {
-                showStatus(
-                  "Error: Failed to save imported settings - " +
-                    chrome.runtime.lastError.message,
-                  true
-                );
-                return;
-              }
-              showStatus("Settings imported successfully. Reloading...");
-              setTimeout(function () {
-                if (typeof restore_options === "function") {
-                  restore_options();
-                } else {
-                  location.reload();
-                }
-              }, 500);
-            });
-          });
-        }
-
-        if (localToImport && Object.keys(localToImport).length > 0) {
-          chrome.storage.local.set(localToImport, function () {
-            if (chrome.runtime.lastError) {
+          persistManagedSyncSettings(settingsToImport, function (error) {
+            if (error) {
               showStatus(
-                "Error: Failed to save local extension data - " +
-                  chrome.runtime.lastError.message,
+                "Error: Failed to save imported settings - " + error.message,
                 true
               );
               return;
             }
-            afterLocalImport();
+            showStatus("Settings imported successfully. Reloading...");
+            setTimeout(function () {
+              if (typeof restore_options === "function") {
+                restore_options();
+              } else {
+                location.reload();
+              }
+            }, 500);
           });
-        } else {
-          afterLocalImport();
         }
+
+        replaceImportableLocalSettings(localToImport, afterLocalImport);
       } catch (err) {
         showStatus("Error: Failed to parse backup file - " + err.message, true);
       }
diff --git a/inject.js b/inject.js
index a100184..1e31adf 100644
--- a/inject.js
+++ b/inject.js
@@ -1,5 +1,6 @@
 var isUserSeek = false; // Track if seek was user-initiated
 var lastToggleSpeed = {}; // Store last toggle speeds per video
+var sharedSettingsDefaults = vscGetSettingsDefaults();
 
 function getPrimaryVideoElement() {
   if (!tc.mediaElements || tc.mediaElements.length === 0) return null;
@@ -12,31 +13,37 @@ function getPrimaryVideoElement() {
 
 var tc = {
   settings: {
-    lastSpeed: 1.0,
-    enabled: true,
+    lastSpeed: sharedSettingsDefaults.lastSpeed,
+    enabled: sharedSettingsDefaults.enabled,
     speeds: {},
-    displayKeyCode: 86,
-    rememberSpeed: false,
-    forceLastSavedSpeed: false,
-    audioBoolean: false,
-    startHidden: false,
-    hideWithYouTubeControls: false,
-    hideWithControls: false,
-    hideWithControlsTimer: 2.0,
-    controllerLocation: "top-left",
-    controllerOpacity: 0.3,
-    controllerMarginTop: 0,
-    controllerMarginRight: 0,
-    controllerMarginBottom: 65,
-    controllerMarginLeft: 0,
-    keyBindings: [],
-    siteRules: [],
-    controllerButtons: ["rewind", "slower", "faster", "advance", "display"],
+    displayKeyCode: sharedSettingsDefaults.displayKeyCode,
+    rememberSpeed: sharedSettingsDefaults.rememberSpeed,
+    forceLastSavedSpeed: sharedSettingsDefaults.forceLastSavedSpeed,
+    audioBoolean: sharedSettingsDefaults.audioBoolean,
+    startHidden: sharedSettingsDefaults.startHidden,
+    hideWithYouTubeControls: sharedSettingsDefaults.hideWithYouTubeControls,
+    hideWithControls: sharedSettingsDefaults.hideWithControls,
+    hideWithControlsTimer: sharedSettingsDefaults.hideWithControlsTimer,
+    controllerLocation: sharedSettingsDefaults.controllerLocation,
+    controllerOpacity: sharedSettingsDefaults.controllerOpacity,
+    controllerMarginTop: sharedSettingsDefaults.controllerMarginTop,
+    controllerMarginRight: sharedSettingsDefaults.controllerMarginRight,
+    controllerMarginBottom: sharedSettingsDefaults.controllerMarginBottom,
+    controllerMarginLeft: sharedSettingsDefaults.controllerMarginLeft,
+    keyBindings: Array.isArray(sharedSettingsDefaults.keyBindings)
+      ? sharedSettingsDefaults.keyBindings.slice()
+      : [],
+    siteRules: Array.isArray(sharedSettingsDefaults.siteRules)
+      ? sharedSettingsDefaults.siteRules.slice()
+      : [],
+    controllerButtons: Array.isArray(sharedSettingsDefaults.controllerButtons)
+      ? sharedSettingsDefaults.controllerButtons.slice()
+      : ["rewind", "slower", "faster", "advance", "display"],
     defaultLogLevel: 3,
     logLevel: 3,
-    enableSubtitleNudge: true, // Enabled by default, but only activates on YouTube
-    subtitleNudgeInterval: 50, // Default 50ms balances subtitle tracking with CPU cost
-    subtitleNudgeAmount: 0.001,
+    enableSubtitleNudge: sharedSettingsDefaults.enableSubtitleNudge,
+    subtitleNudgeInterval: sharedSettingsDefaults.subtitleNudgeInterval,
+    subtitleNudgeAmount: sharedSettingsDefaults.subtitleNudgeAmount,
     customButtonIcons: {}
   },
   mediaElements: [],
@@ -184,6 +191,8 @@ function createDefaultBinding(action, key, keyCode, value) {
     action: action,
     key: key,
     keyCode: keyCode,
+    code: null,
+    disabled: false,
     value: value,
     force: false,
     predefined: true
@@ -220,7 +229,7 @@ function defaultKeyBindings(storage) {
       "reset",
       "R",
       Number(storage.resetKeyCode) || 82,
-      1.0
+      0
     ),
     createDefaultBinding(
       "fast",
@@ -429,6 +438,165 @@ function applyControllerLocation(videoController, location) {
   );
 }
 
+function getYouTubeAutoHidePlayer(video) {
+  if (!video || !isOnYouTube()) return null;
+
+  return video.closest(".html5-video-player") || video.closest("#movie_player");
+}
+
+function getAutoHideModeForVideo(video) {
+  if (!tc.settings.hideWithControls) return "off";
+  return getYouTubeAutoHidePlayer(video) ? "youtube" : "generic";
+}
+
+function getControllerMountParent(video, parentHint) {
+  var parentEl = parentHint || (video && (video.parentElement || video.parentNode));
+  if (!parentEl) return null;
+
+  switch (true) {
+    case location.hostname == "www.amazon.com":
+    case location.hostname == "www.reddit.com":
+    case /hbogo\./.test(location.hostname):
+      return parentEl.parentElement || parentEl;
+    case location.hostname == "www.facebook.com":
+      var facebookParent = parentEl;
+      for (
+        var depth = 0;
+        depth < 8 && facebookParent && facebookParent.parentElement;
+        depth++
+      ) {
+        facebookParent = facebookParent.parentElement;
+      }
+      return facebookParent || parentEl;
+    case location.hostname == "tv.apple.com":
+      var root = parentEl.getRootNode();
+      var scrim = root && root.querySelector ? root.querySelector(".scrim") : null;
+      return scrim || parentEl;
+    case location.hostname == "www.youtube.com":
+    case location.hostname == "m.youtube.com":
+    case location.hostname == "music.youtube.com":
+      return getYouTubeAutoHidePlayer(video) || parentEl;
+    default:
+      return parentEl;
+  }
+}
+
+function getControllerBehaviorSignature(video) {
+  return JSON.stringify({
+    startHidden: Boolean(tc.settings.startHidden),
+    hideWithControls: Boolean(tc.settings.hideWithControls),
+    hideWithControlsTimer: Number(tc.settings.hideWithControlsTimer),
+    controllerLocation: normalizeControllerLocation(tc.settings.controllerLocation),
+    controllerOpacity: Number(tc.settings.controllerOpacity),
+    controllerMarginTop: normalizeControllerMarginPx(tc.settings.controllerMarginTop, 0),
+    controllerMarginBottom: normalizeControllerMarginPx(
+      tc.settings.controllerMarginBottom,
+      0
+    ),
+    controllerButtons: Array.isArray(tc.settings.controllerButtons)
+      ? tc.settings.controllerButtons.slice()
+      : [],
+    enableSubtitleNudge: Boolean(tc.settings.enableSubtitleNudge),
+    subtitleNudgeInterval: Number(tc.settings.subtitleNudgeInterval),
+    autoHideMode: getAutoHideModeForVideo(video),
+    mediaTag: video && video.tagName ? video.tagName : ""
+  });
+}
+
+function rebuildControllerForVideo(video, parentHint, reason) {
+  if (!video) return null;
+
+  var previous = video.vsc || null;
+  var preservedState = previous
+    ? {
+      mark: previous.mark,
+      resetToggleArmed: previous.resetToggleArmed === true,
+      subtitleNudgeEnabledOverride: previous.subtitleNudgeEnabledOverride,
+      userHidden:
+        Boolean(previous.div) &&
+        previous.div.classList.contains("vsc-hidden")
+    }
+    : null;
+
+  if (previous) {
+    previous.remove();
+  }
+
+  if (!video.isConnected || !hasUsableMediaSource(video)) {
+    return null;
+  }
+
+  var nextController = new tc.videoController(
+    video,
+    parentHint || video.parentElement || video.parentNode
+  );
+  if (!nextController) return null;
+
+  if (preservedState) {
+    nextController.mark = preservedState.mark;
+    nextController.resetToggleArmed = preservedState.resetToggleArmed;
+
+    if (
+      typeof preservedState.subtitleNudgeEnabledOverride === "boolean"
+    ) {
+      nextController.subtitleNudgeEnabledOverride =
+        preservedState.subtitleNudgeEnabledOverride;
+      updateSubtitleNudgeIndicator(video);
+      if (!preservedState.subtitleNudgeEnabledOverride) {
+        nextController.stopSubtitleNudge();
+      } else if (!video.paused && video.playbackRate !== 1.0) {
+        nextController.startSubtitleNudge();
+      }
+    }
+
+    if (preservedState.userHidden && nextController.div) {
+      nextController.div.classList.add("vsc-hidden");
+    }
+  }
+
+  log("Rebuilt controller: " + (reason || "refresh"), 4);
+  return nextController;
+}
+
+function refreshManagedController(video, parentHint) {
+  if (!video || !video.vsc) return null;
+  if (!video.isConnected) {
+    removeController(video);
+    return null;
+  }
+
+  var controller = video.vsc;
+  controller.parent = video.parentElement || parentHint || controller.parent;
+
+  var expectedMountParent = getControllerMountParent(video, controller.parent);
+  var nextSignature = getControllerBehaviorSignature(video);
+  var wrapper = controller.div;
+  var needsRebuild =
+    !wrapper ||
+    !wrapper.isConnected ||
+    !expectedMountParent ||
+    wrapper.parentNode !== expectedMountParent ||
+    controller.behaviorSignature !== nextSignature;
+
+  if (needsRebuild) {
+    return rebuildControllerForVideo(
+      video,
+      controller.parent,
+      "DOM/source/site-rule change"
+    );
+  }
+
+  controller.mountParent = expectedMountParent;
+  controller.behaviorSignature = nextSignature;
+  applyControllerLocation(controller, tc.settings.controllerLocation);
+  var controllerEl = getControllerElement(controller);
+  if (controllerEl) {
+    controllerEl.style.opacity = String(tc.settings.controllerOpacity);
+  }
+  updateSubtitleNudgeIndicator(video);
+  return controller;
+}
+
 function captureSiteRuleBase() {
   tc.siteRuleBase = {
     startHidden: tc.settings.startHidden,
@@ -776,27 +944,40 @@ function setSubtitleNudgeEnabledForVideo(video, enabled) {
   return normalizedEnabled;
 }
 
-function subtitleNudgeIconMarkup(isEnabled) {
+function renderSubtitleNudgeIndicatorContent(target, isEnabled) {
+  if (!target) return;
   var action = isEnabled ? "subtitleNudgeOn" : "subtitleNudgeOff";
   var custom =
     tc.settings.customButtonIcons &&
     tc.settings.customButtonIcons[action] &&
     tc.settings.customButtonIcons[action].svg;
+  vscClearElement(target);
   if (custom) {
-    return (
-      '<span class="vsc-btn-icon" aria-hidden="true">' + custom + "</span>"
+    var customWrap = vscCreateSvgWrap(
+      target.ownerDocument || document,
+      custom,
+      "vsc-btn-icon"
     );
+    if (customWrap) {
+      target.appendChild(customWrap);
+      return;
+    }
   }
   if (typeof vscIconSvgString !== "function") {
-    return isEnabled ? "✓" : "×";
+    target.textContent = isEnabled ? "✓" : "×";
+    return;
   }
   var svg = vscIconSvgString(action, 14);
   if (!svg) {
-    return isEnabled ? "✓" : "×";
+    target.textContent = isEnabled ? "✓" : "×";
+    return;
   }
-  return (
-    '<span class="vsc-btn-icon" aria-hidden="true">' + svg + "</span>"
-  );
+  var wrap = vscCreateSvgWrap(target.ownerDocument || document, svg, "vsc-btn-icon");
+  if (wrap) {
+    target.appendChild(wrap);
+    return;
+  }
+  target.textContent = isEnabled ? "✓" : "×";
 }
 
 function updateSubtitleNudgeIndicator(video) {
@@ -804,11 +985,10 @@ function updateSubtitleNudgeIndicator(video) {
 
   var isEnabled = isSubtitleNudgeEnabledForVideo(video);
   var title = isEnabled ? "Subtitle nudge enabled" : "Subtitle nudge disabled";
-  var mark = subtitleNudgeIconMarkup(isEnabled);
 
   var indicator = video.vsc.subtitleNudgeIndicator;
   if (indicator) {
-    indicator.innerHTML = mark;
+    renderSubtitleNudgeIndicatorContent(indicator, isEnabled);
     indicator.dataset.enabled = isEnabled ? "true" : "false";
     indicator.dataset.supported = "true";
     indicator.title = title;
@@ -817,7 +997,7 @@ function updateSubtitleNudgeIndicator(video) {
 
   var flashEl = video.vsc.nudgeFlashIndicator;
   if (flashEl) {
-    flashEl.innerHTML = mark;
+    renderSubtitleNudgeIndicatorContent(flashEl, isEnabled);
     flashEl.dataset.enabled = isEnabled ? "true" : "false";
     flashEl.dataset.supported = "true";
     flashEl.setAttribute("aria-label", title);
@@ -898,8 +1078,8 @@ function applySourceTransitionPolicy(video, forceUpdate) {
     setSpeed(video, desiredSpeed, false, false);
   }
 
-  // Same-tab SPA (e.g. YouTube watch → Shorts): URL can change while remember-speed
-  // already ran on src mutation — re-apply margins / location / opacity for new rules.
+  // Same-tab SPA or DOM-driven player swaps can change the effective rule output
+  // after the media source updates, so refresh or rebuild controllers here too.
   reapplySiteRulesAndControllerGeometry();
 }
 
@@ -1021,8 +1201,14 @@ function hasUsableMediaSource(node) {
 }
 
 function ensureController(node, parent) {
-  if (!isMediaElement(node) || node.vsc) return node && node.vsc;
-  if (!hasUsableMediaSource(node)) {
+  if (!isMediaElement(node)) return node && node.vsc;
+
+  if (!node.isConnected) {
+    removeController(node);
+    return null;
+  }
+
+  if (!node.vsc && !hasUsableMediaSource(node)) {
     log(
       `Deferring controller creation for ${node.tagName}: no usable source yet`,
       5
@@ -1033,9 +1219,13 @@ function ensureController(node, parent) {
   // href selects site rules; re-run on every new/usable media so margins/opacity match current URL.
   var siteDisabled = applySiteRuleOverrides();
   if (!tc.settings.enabled || siteDisabled) {
+    removeController(node);
     return null;
   }
-  refreshAllControllerGeometry();
+
+  if (node.vsc) {
+    return refreshManagedController(node, parent);
+  }
 
   log(
     `Creating controller for ${node.tagName}: ${node.src || node.currentSrc || "no src"}`,
@@ -1179,7 +1369,8 @@ function log(message, level) {
   }
 }
 
-chrome.storage.sync.get(tc.settings, function (storage) {
+chrome.storage.sync.get(null, function (storage) {
+  storage = vscExpandStoredSettings(storage);
   var storedBindings = Array.isArray(storage.keyBindings)
     ? storage.keyBindings
     : [];
@@ -1190,19 +1381,6 @@ chrome.storage.sync.get(tc.settings, function (storage) {
 
   if (tc.settings.keyBindings.length === 0) {
     tc.settings.keyBindings = defaultKeyBindings(storage);
-    tc.settings.version = "0.5.3";
-    chrome.storage.sync.set({
-      keyBindings: tc.settings.keyBindings,
-      version: tc.settings.version,
-      displayKeyCode: tc.settings.displayKeyCode,
-      rememberSpeed: tc.settings.rememberSpeed,
-      forceLastSavedSpeed: tc.settings.forceLastSavedSpeed,
-      audioBoolean: tc.settings.audioBoolean,
-      startHidden: tc.settings.startHidden,
-      enabled: tc.settings.enabled,
-      controllerLocation: tc.settings.controllerLocation,
-      controllerOpacity: tc.settings.controllerOpacity
-    });
   }
   tc.settings.lastSpeed = Number(storage.lastSpeed);
   if (!isValidSpeed(tc.settings.lastSpeed) && tc.settings.lastSpeed !== 1.0) {
@@ -1280,7 +1458,14 @@ chrome.storage.sync.get(tc.settings, function (storage) {
     addedDefaultBinding;
 
   if (addedDefaultBinding) {
-    chrome.storage.sync.set({ keyBindings: tc.settings.keyBindings });
+    var keyBindingsDiff = vscBuildStoredSettingsDiff({
+      keyBindings: tc.settings.keyBindings
+    });
+    if (Object.prototype.hasOwnProperty.call(keyBindingsDiff, "keyBindings")) {
+      chrome.storage.sync.set({ keyBindings: keyBindingsDiff.keyBindings });
+    } else {
+      chrome.storage.sync.remove("keyBindings");
+    }
   }
   captureSiteRuleBase();
   patchAttachShadow();
@@ -1357,12 +1542,15 @@ chrome.storage.sync.get(tc.settings, function (storage) {
                 tc.settings.customButtonIcons &&
                 tc.settings.customButtonIcons[act] &&
                 tc.settings.customButtonIcons[act].svg;
-              btn.innerHTML = "";
+              vscClearElement(btn);
               if (svg) {
-                var cw = doc.createElement("span");
-                cw.className = "vsc-btn-icon";
-                cw.innerHTML = svg;
-                btn.appendChild(cw);
+                var cw = vscCreateSvgWrap(doc, svg, "vsc-btn-icon");
+                if (cw) {
+                  btn.appendChild(cw);
+                } else {
+                  var cdf = controllerButtonDefs[act];
+                  btn.textContent = (cdf && cdf.label) || "?";
+                }
               } else if (typeof vscIconWrap === "function") {
                 var wrap = vscIconWrap(doc, act, 14);
                 if (wrap) {
@@ -1405,10 +1593,12 @@ function createControllerButton(doc, action, label, className) {
     tc.settings.customButtonIcons[action] &&
     tc.settings.customButtonIcons[action].svg;
   if (custom) {
-    var customWrap = doc.createElement("span");
-    customWrap.className = "vsc-btn-icon";
-    customWrap.innerHTML = custom;
-    button.appendChild(customWrap);
+    var customWrap = vscCreateSvgWrap(doc, custom, "vsc-btn-icon");
+    if (customWrap) {
+      button.appendChild(customWrap);
+    } else {
+      button.textContent = label || "?";
+    }
   } else if (typeof vscIconWrap === "function") {
     var wrap = vscIconWrap(doc, action, 14);
     if (wrap) {
@@ -1466,7 +1656,14 @@ function defineVideoController() {
       return;
     }
 
-    log(`Controller created and attached to DOM. Hidden: ${this.div.classList.contains('vsc-hidden')}`, 4);
+    this.mountParent =
+      this.div.parentNode || getControllerMountParent(target, this.parent);
+    this.behaviorSignature = getControllerBehaviorSignature(target);
+
+    log(
+      `Controller created and attached to DOM. Hidden: ${this.div.classList.contains('vsc-hidden')}`,
+      4
+    );
 
     var mediaEventAction = function (event) {
       if (
@@ -1740,10 +1937,10 @@ function defineVideoController() {
   };
 
   tc.videoController.prototype.setupYouTubeAutoHide = function (wrapper) {
-    if (!wrapper || !isOnYouTube()) return;
+    if (!wrapper) return;
 
     const video = this.video;
-    const ytPlayer = video.closest(".html5-video-player");
+    const ytPlayer = getYouTubeAutoHidePlayer(video);
     if (!ytPlayer) {
       log("YouTube player not found for auto-hide setup", 4);
       return;
@@ -1883,7 +2080,8 @@ function defineVideoController() {
       wrapper.classList.add("vsc-nosource");
     if (tc.settings.startHidden) wrapper.classList.add("vsc-hidden");
     // Use lower z-index for non-YouTube sites to avoid overlapping modals
-    if (!isOnYouTube()) wrapper.classList.add("vsc-non-youtube");
+    if (!getYouTubeAutoHidePlayer(this.video))
+      wrapper.classList.add("vsc-non-youtube");
     var shadow = wrapper.attachShadow({ mode: "open" });
     var shadowStylesheet = doc.createElement("link");
     shadowStylesheet.rel = "stylesheet";
@@ -1999,7 +2197,7 @@ function defineVideoController() {
 
     // Setup auto-hide observers if enabled
     if (tc.settings.hideWithControls) {
-      if (isOnYouTube()) {
+      if (getAutoHideModeForVideo(this.video) === "youtube") {
         this.setupYouTubeAutoHide(wrapper);
       } else {
         this.setupGenericAutoHide(wrapper);
@@ -2071,60 +2269,26 @@ function defineVideoController() {
   };
 }
 
-function escapeStringRegExp(str) {
-  const m = /[|\\{}()[\]^$+*?.]/g;
-  return str.replace(m, "\\$&");
-}
 function applySiteRuleOverrides() {
   resetSettingsFromSiteRuleBase();
+  tc.activeSiteRule = null;
 
   if (!Array.isArray(tc.settings.siteRules) || tc.settings.siteRules.length === 0) {
     return false;
   }
 
   var currentUrl = location.href;
-  var matchedRule = null;
-
-  for (var i = 0; i < tc.settings.siteRules.length; i++) {
-    var rule = tc.settings.siteRules[i];
-    var pattern = rule.pattern;
-    if (!pattern || pattern.length === 0) continue;
-
-    var regex;
-    if (pattern.startsWith("/") && pattern.lastIndexOf("/") > 0) {
-      try {
-        var lastSlash = pattern.lastIndexOf("/");
-        regex = new RegExp(
-          pattern.substring(1, lastSlash),
-          pattern.substring(lastSlash + 1)
-        );
-      } catch (e) {
-        log(`Invalid site rule regex: ${pattern}. ${e.message}`, 2);
-        continue;
-      }
-    } else {
-      regex = new RegExp(escapeStringRegExp(pattern));
-    }
-
-    if (regex && regex.test(currentUrl)) {
-      matchedRule = rule;
-      break;
-    }
-  }
+  var matchedRule = vscMatchSiteRule(currentUrl, tc.settings.siteRules);
 
   if (!matchedRule) return false;
 
   tc.activeSiteRule = matchedRule;
-  log(`Matched site rule: ${matchedRule.pattern}`, 4);
+  log("Matched site rule overrides for current URL", 4);
 
   // Check if extension should be enabled/disabled on this site
-  if (matchedRule.enabled === false) {
+  if (vscIsSiteRuleDisabled(matchedRule)) {
     log(`Extension disabled for site: ${currentUrl}`, 4);
     return true;
-  } else if (matchedRule.disableExtension === true) {
-    // Handle old format
-    log(`Extension disabled (legacy) for site: ${currentUrl}`, 4);
-    return true;
   }
 
   // Override general settings with site-specific overrides
@@ -2182,23 +2346,22 @@ function applySiteRuleOverrides() {
   return false;
 }
 
-/** Apply current tc.settings controller layout/opacity to every attached controller (after site rules). */
-function refreshAllControllerGeometry() {
-  tc.mediaElements.forEach(function (video) {
-    if (!video || !video.vsc) return;
-    applyControllerLocation(video.vsc, tc.settings.controllerLocation);
-    var controllerEl = getControllerElement(video.vsc);
-    if (controllerEl) {
-      controllerEl.style.opacity = String(tc.settings.controllerOpacity);
-    }
-  });
-}
-
-/** Re-match site rules for current URL and refresh controller position/opacity on every video. */
+/** Re-match site rules for current URL and refresh or rebuild every controller. */
 function reapplySiteRulesAndControllerGeometry() {
   var siteDisabled = applySiteRuleOverrides();
-  if (!tc.settings.enabled || siteDisabled) return;
-  refreshAllControllerGeometry();
+  var videos = tc.mediaElements.slice();
+
+  if (!tc.settings.enabled || siteDisabled) {
+    videos.forEach(function (video) {
+      removeController(video);
+    });
+    return;
+  }
+
+  videos.forEach(function (video) {
+    if (!video) return;
+    ensureController(video, video.parentElement || video.parentNode);
+  });
 }
 
 function shouldPreserveDesiredSpeed(video, speed) {
@@ -2539,7 +2702,6 @@ function initializeNow(doc, forceReinit = false) {
   if ((!forceReinit && vscInitializedDocuments.has(doc)) || !doc.body) return;
 
   var siteDisabled = applySiteRuleOverrides();
-  if (!tc.settings.enabled || siteDisabled) return;
 
   if (!doc.body.classList.contains("vsc-initialized")) {
     doc.body.classList.add("vsc-initialized");
@@ -2551,7 +2713,9 @@ function initializeNow(doc, forceReinit = false) {
 
   if (forceReinit) {
     log("Force re-initialization requested", 4);
-    refreshAllControllerGeometry();
+    reapplySiteRulesAndControllerGeometry();
+  } else if (!tc.settings.enabled || siteDisabled) {
+    reapplySiteRulesAndControllerGeometry();
   }
 
   vscInitializedDocuments.add(doc);
diff --git a/lucide-client.js b/lucide-client.js
index 41727d0..ac4581b 100644
--- a/lucide-client.js
+++ b/lucide-client.js
@@ -31,32 +31,9 @@ function sanitizeLucideSvg(svgText) {
   var t = String(svgText).replace(/\0/g, "").trim();
   if (!/<svg[\s>]/i.test(t)) return null;
   var doc = new DOMParser().parseFromString(t, "image/svg+xml");
-  var svg = doc.querySelector("svg");
+  if (doc.querySelector("parsererror")) return null;
+  var svg = vscSanitizeSvgTree(doc.querySelector("svg"));
   if (!svg) return null;
-  svg.querySelectorAll("script").forEach(function (n) {
-    n.remove();
-  });
-  svg.querySelectorAll("style").forEach(function (n) {
-    n.remove();
-  });
-  svg.querySelectorAll("*").forEach(function (el) {
-    for (var i = el.attributes.length - 1; i >= 0; i--) {
-      var attr = el.attributes[i];
-      var name = attr.name.toLowerCase();
-      var val = attr.value;
-      if (name.indexOf("on") === 0) {
-        el.removeAttribute(attr.name);
-        continue;
-      }
-      if (
-        (name === "href" || name === "xlink:href") &&
-        /^javascript:/i.test(val)
-      ) {
-        el.removeAttribute(attr.name);
-      }
-    }
-  });
-  svg.setAttribute("xmlns", "http://www.w3.org/2000/svg");
   svg.removeAttribute("width");
   svg.removeAttribute("height");
   svg.setAttribute("width", "100%");
diff --git a/manifest.json b/manifest.json
index db84a0d..fc70a61 100644
--- a/manifest.json
+++ b/manifest.json
@@ -1,7 +1,7 @@
 {
   "name": "Speeder",
   "short_name": "Speeder",
-  "version": "5.1.5",
+  "version": "5.1.7",
   "manifest_version": 2,
   "description": "Speed up, slow down, advance and rewind HTML5 audio/video with shortcuts (New and improved version of \"Video Speed Controller\")",
   "homepage_url": "https://github.com/SoPat712/speeder",
@@ -59,6 +59,7 @@
         "inject.css"
       ],
       "js": [
+        "settings-core.js",
         "ui-icons.js",
         "inject.js"
       ]
diff --git a/options.html b/options.html
index 3d5be8d..4152b0d 100644
--- a/options.html
+++ b/options.html
@@ -5,6 +5,7 @@
     <meta name="viewport" content="width=device-width, initial-scale=1" />
     <title>Speeder Settings</title>
     <link rel="stylesheet" href="options.css" />
+    <script src="settings-core.js"></script>
     <script src="ui-icons.js"></script>
     <script src="lucide-client.js"></script>
     <script src="options.js"></script>
@@ -550,18 +551,29 @@
                     <span>Override auto-hide for this site</span>
                     <input type="checkbox" class="override-autohide" />
                   </label>
-                  <div class="site-autohide-container" style="display: none">
-                    <div class="site-rule-option site-rule-option-checkbox">
-                      <label class="site-rule-split-label">
-                        <span>Hide with controls (idle-based)</span>
-                        <input type="checkbox" class="site-hideWithControls" />
-                      </label>
+                    <div class="site-autohide-container" style="display: none">
+                      <div class="site-rule-option site-rule-option-checkbox">
+                        <label class="site-rule-split-label">
+                          <span
+                            >Hide with controls<br /><em
+                              >Fade the controller in and out with the video
+                              interface: perfect sync on YouTube, idle-based
+                              elsewhere.</em
+                            ></span
+                          >
+                          <input type="checkbox" class="site-hideWithControls" />
+                        </label>
+                      </div>
+                      <div class="site-rule-option site-rule-option-field">
+                        <label
+                          >Auto-hide timer (seconds)<br /><em
+                            >Seconds of inactivity before hiding: 0.1&ndash;15
+                            for non-YouTube sites.</em
+                          ></label
+                        >
+                        <input type="text" class="site-hideWithControlsTimer" />
+                      </div>
                     </div>
-                    <div class="site-rule-option site-rule-option-field">
-                      <label>Auto-hide timer (0.1&ndash;15s):</label>
-                      <input type="text" class="site-hideWithControlsTimer" />
-                    </div>
-                  </div>
                 </div>
                 <div class="site-rule-override-section">
                   <label class="site-override-lead">
diff --git a/options.js b/options.js
index e280f1e..425b609 100644
--- a/options.js
+++ b/options.js
@@ -172,8 +172,9 @@ var customButtonIconsLive = {};
 
 function fillControlBarIconElement(icon, buttonId) {
   if (!icon || !buttonId) return;
+  var doc = icon.ownerDocument || document;
   if (buttonId === "nudge") {
-    icon.innerHTML = "";
+    vscClearElement(icon);
     icon.className = "cb-icon cb-icon-nudge-pair";
     function nudgeChipMarkup(action) {
       var c = customButtonIconsLive[action];
@@ -189,10 +190,10 @@ function fillControlBarIconElement(icon, buttonId) {
       sp.setAttribute("data-nudge-state", stateKey);
       var inner = nudgeChipMarkup(action);
       if (inner) {
-        var wrap = document.createElement("span");
-        wrap.className = "vsc-btn-icon";
-        wrap.innerHTML = inner;
-        sp.appendChild(wrap);
+        var wrap = vscCreateSvgWrap(doc, inner, "vsc-btn-icon");
+        if (wrap) {
+          sp.appendChild(wrap);
+        }
       }
       icon.appendChild(sp);
     }
@@ -207,16 +208,15 @@ function fillControlBarIconElement(icon, buttonId) {
   icon.className = "cb-icon";
   var custom = customButtonIconsLive[buttonId];
   if (custom && custom.svg) {
-    icon.innerHTML = custom.svg;
-    return;
+    if (vscSetSvgContent(icon, custom.svg)) return;
   }
   if (typeof vscIconSvgString === "function") {
     var svgHtml = vscIconSvgString(buttonId, 16);
     if (svgHtml) {
-      icon.innerHTML = svgHtml;
-      return;
+      if (vscSetSvgContent(icon, svgHtml)) return;
     }
   }
+  vscClearElement(icon);
   var def = controllerButtonDefs[buttonId];
   icon.textContent = (def && def.icon) || "?";
 }
@@ -226,64 +226,48 @@ function createDefaultBinding(action, key, keyCode, value) {
     action: action,
     key: key,
     keyCode: keyCode,
+    code: null,
+    disabled: false,
     value: value,
     force: false,
     predefined: true
   };
 }
 
-var tcDefaults = {
-  speed: 1.0,
-  lastSpeed: 1.0,
-  displayKeyCode: 86,
-  rememberSpeed: false,
-  audioBoolean: false,
-  startHidden: false,
-  hideWithYouTubeControls: false,
-  hideWithControls: false,
-  hideWithControlsTimer: 2.0,
-  controllerLocation: "top-left",
-  forceLastSavedSpeed: false,
-  enabled: true,
-  controllerOpacity: 0.3,
-  controllerMarginTop: 0,
-  controllerMarginRight: 0,
-  controllerMarginBottom: 65,
-  controllerMarginLeft: 0,
-  keyBindings: [
-    createDefaultBinding("display", "V", 86, 0),
-    createDefaultBinding("move", "P", 80, 0),
-    createDefaultBinding("slower", "S", 83, 0.1),
-    createDefaultBinding("faster", "D", 68, 0.1),
-    createDefaultBinding("rewind", "Z", 90, 10),
-    createDefaultBinding("advance", "X", 88, 10),
-    createDefaultBinding("reset", "R", 82, 1),
-    createDefaultBinding("fast", "G", 71, 1.8),
-    createDefaultBinding("toggleSubtitleNudge", "N", 78, 0)
-  ],
-  siteRules: [
-    {
-      pattern: "/^https:\\/\\/(www\\.)?youtube\\.com\\/(?!shorts\\/).*/",
-      enabled: true,
-      enableSubtitleNudge: true,
-      subtitleNudgeInterval: 50
-    },
-    {
-      pattern: "/^https:\\/\\/(www\\.)?youtube\\.com\\/shorts\\/.*/",
-      enabled: true,
-      rememberSpeed: true,
-      controllerMarginTop: 60,
-      controllerMarginBottom: 85
+var tcDefaults = vscGetSettingsDefaults();
+var legacySyncKeys = [
+  "resetSpeed",
+  "speedStep",
+  "fastSpeed",
+  "rewindTime",
+  "advanceTime",
+  "resetKeyCode",
+  "slowerKeyCode",
+  "fasterKeyCode",
+  "rewindKeyCode",
+  "advanceKeyCode",
+  "fastKeyCode",
+  "blacklist"
+];
+
+function persistManagedSyncSettings(settings, callback) {
+  var nextSettings = vscBuildStoredSettingsDiff(settings);
+  chrome.storage.sync.remove(vscGetManagedSyncKeys(), function () {
+    if (chrome.runtime.lastError) {
+      callback(chrome.runtime.lastError);
+      return;
     }
-  ],
-  controllerButtons: ["rewind", "slower", "faster", "advance", "display"],
-  showPopupControlBar: true,
-  popupMatchHoverControls: true,
-  popupControllerButtons: ["rewind", "slower", "faster", "advance", "display"],
-  enableSubtitleNudge: false,
-  subtitleNudgeInterval: 50,
-  subtitleNudgeAmount: 0.001
-};
+
+    if (Object.keys(nextSettings).length === 0) {
+      callback(null);
+      return;
+    }
+
+    chrome.storage.sync.set(nextSettings, function () {
+      callback(chrome.runtime.lastError || null);
+    });
+  });
+}
 
 const actionLabels = {
   display: "Show/hide controller",
@@ -889,15 +873,20 @@ function save_options() {
     settings.siteRules.push(rule);
   });
 
-  // Legacy keys to remove
-  const legacyKeys = [
-    "resetSpeed", "speedStep", "fastSpeed", "rewindTime", "advanceTime",
-    "resetKeyCode", "slowerKeyCode", "fasterKeyCode", "rewindKeyCode",
-    "advanceKeyCode", "fastKeyCode", "blacklist"
-  ];
+  chrome.storage.sync.remove(legacySyncKeys, function () {
+    if (chrome.runtime.lastError) {
+      status.textContent =
+        "Error: Failed to clear legacy settings - " +
+        chrome.runtime.lastError.message;
+      return;
+    }
 
-  chrome.storage.sync.remove(legacyKeys, function () {
-    chrome.storage.sync.set(settings, function () {
+    persistManagedSyncSettings(settings, function (error) {
+      if (error) {
+        status.textContent =
+          "Error: Failed to save settings - " + error.message;
+        return;
+      }
       status.textContent = "Options saved";
       setTimeout(function () {
         status.textContent = "";
@@ -1200,8 +1189,8 @@ function createControlBarBlock(buttonId) {
 }
 
 function populateControlBarZones(activeZone, availableZone, activeIds, allowButtonId) {
-  activeZone.innerHTML = "";
-  availableZone.innerHTML = "";
+  vscClearElement(activeZone);
+  vscClearElement(availableZone);
 
   var allowed = function (id) {
     if (!controllerButtonDefs[id]) return false;
@@ -1394,7 +1383,7 @@ function initLucideButtonIconsUI() {
 
   if (!actionSel.dataset.lucideInit) {
     actionSel.dataset.lucideInit = "1";
-    actionSel.innerHTML = "";
+    vscClearElement(actionSel);
     Object.keys(controllerButtonDefs).forEach(function (aid) {
       if (aid === "nudge") {
         Object.keys(lucideSubtitleNudgeActionLabels).forEach(function (subId) {
@@ -1415,7 +1404,7 @@ function initLucideButtonIconsUI() {
   }
 
   function renderResults(slugs) {
-    resultsEl.innerHTML = "";
+    vscClearElement(resultsEl);
     slugs.forEach(function (slug) {
       var b = document.createElement("button");
       b.type = "button";
@@ -1450,11 +1439,13 @@ function initLucideButtonIconsUI() {
           .then(function (txt) {
             var safe = sanitizeLucideSvg(txt);
             if (!safe) throw new Error("Bad SVG");
-            previewEl.innerHTML = safe;
+            if (!vscSetSvgContent(previewEl, safe)) {
+              throw new Error("Preview render failed");
+            }
             setLucideStatus("Preview: " + slug);
           })
           .catch(function (e) {
-            previewEl.innerHTML = "";
+            vscClearElement(previewEl);
             setLucideStatus(
               "Could not load: " + slug + " — " + e.message
             );
@@ -1473,7 +1464,7 @@ function initLucideButtonIconsUI() {
           .then(function (map) {
             var q = searchInput.value;
             if (!q.trim()) {
-              resultsEl.innerHTML = "";
+              vscClearElement(resultsEl);
               return;
             }
             renderResults(searchLucideSlugs(map, q, 48));
@@ -1557,53 +1548,49 @@ function initLucideButtonIconsUI() {
 }
 
 function restore_options() {
-  chrome.storage.sync.get(tcDefaults, function (storage) {
+  chrome.storage.sync.get(null, function (storage) {
+    var settings = vscExpandStoredSettings(storage);
     chrome.storage.local.get(["customButtonIcons"], function (loc) {
       customButtonIconsLive =
         loc && loc.customButtonIcons && typeof loc.customButtonIcons === "object"
           ? loc.customButtonIcons
           : {};
 
-    document.getElementById("rememberSpeed").checked = storage.rememberSpeed;
+    document.getElementById("rememberSpeed").checked = settings.rememberSpeed;
     document.getElementById("forceLastSavedSpeed").checked =
-      storage.forceLastSavedSpeed;
-    document.getElementById("audioBoolean").checked = storage.audioBoolean;
-    document.getElementById("enabled").checked = storage.enabled;
-    document.getElementById("startHidden").checked = storage.startHidden;
-
-    // Migration/Normalization for hideWithControls
-    const hideWithControls = typeof storage.hideWithControls !== "undefined"
-      ? storage.hideWithControls
-      : storage.hideWithYouTubeControls;
-    
-    document.getElementById("hideWithControls").checked = hideWithControls;
+      settings.forceLastSavedSpeed;
+    document.getElementById("audioBoolean").checked = settings.audioBoolean;
+    document.getElementById("enabled").checked = settings.enabled;
+    document.getElementById("startHidden").checked = settings.startHidden;
+    document.getElementById("hideWithControls").checked =
+      settings.hideWithControls;
     document.getElementById("hideWithControlsTimer").value = 
-      storage.hideWithControlsTimer || tcDefaults.hideWithControlsTimer;
+      settings.hideWithControlsTimer || tcDefaults.hideWithControlsTimer;
 
     document.getElementById("controllerLocation").value =
-      normalizeControllerLocation(storage.controllerLocation);
+      normalizeControllerLocation(settings.controllerLocation);
     document.getElementById("controllerOpacity").value =
-      storage.controllerOpacity;
+      settings.controllerOpacity;
     document.getElementById("controllerMarginTop").value =
-      storage.controllerMarginTop ?? tcDefaults.controllerMarginTop;
+      settings.controllerMarginTop ?? tcDefaults.controllerMarginTop;
     document.getElementById("controllerMarginBottom").value =
-      storage.controllerMarginBottom ?? tcDefaults.controllerMarginBottom;
+      settings.controllerMarginBottom ?? tcDefaults.controllerMarginBottom;
     document.getElementById("showPopupControlBar").checked =
-      storage.showPopupControlBar !== false;
+      settings.showPopupControlBar !== false;
     document.getElementById("enableSubtitleNudge").checked =
-      storage.enableSubtitleNudge;
+      settings.enableSubtitleNudge;
     document.getElementById("subtitleNudgeInterval").value =
-      storage.subtitleNudgeInterval;
+      settings.subtitleNudgeInterval;
 
-    if (!Array.isArray(storage.keyBindings) || storage.keyBindings.length === 0) {
-      storage.keyBindings = tcDefaults.keyBindings.slice();
+    if (!Array.isArray(settings.keyBindings) || settings.keyBindings.length === 0) {
+      settings.keyBindings = tcDefaults.keyBindings.slice();
     }
 
-    ensureAllDefaultBindings(storage);
+    ensureAllDefaultBindings(settings);
 
     document.querySelectorAll(".customs:not([id])").forEach((row) => row.remove());
 
-    storage.keyBindings.forEach((item) => {
+    settings.keyBindings.forEach((item) => {
       var row = document.getElementById(item.action);
       var normalizedBinding = normalizeStoredBinding(item);
 
@@ -1632,13 +1619,11 @@ function restore_options() {
 
     refreshAddShortcutSelector();
 
-    // Load site rules (use defaults if none in storage or empty array)
-    var siteRules =
-      Array.isArray(storage.siteRules) && storage.siteRules.length > 0
-        ? storage.siteRules
-        : tcDefaults.siteRules || [];
+    var siteRules = Array.isArray(settings.siteRules)
+      ? settings.siteRules
+      : tcDefaults.siteRules || [];
 
-    document.getElementById("siteRulesContainer").innerHTML = "";
+    vscClearElement(document.getElementById("siteRulesContainer"));
     if (siteRules.length > 0) {
       siteRules.forEach((rule) => {
         if (rule && rule.pattern) {
@@ -1647,16 +1632,16 @@ function restore_options() {
       });
     }
 
-    var controllerButtons = Array.isArray(storage.controllerButtons)
-      ? storage.controllerButtons
+    var controllerButtons = Array.isArray(settings.controllerButtons)
+      ? settings.controllerButtons
       : tcDefaults.controllerButtons;
     populateControlBarEditor(controllerButtons);
 
     document.getElementById("popupMatchHoverControls").checked =
-      storage.popupMatchHoverControls !== false;
+      settings.popupMatchHoverControls !== false;
 
-    var popupButtons = Array.isArray(storage.popupControllerButtons)
-      ? storage.popupControllerButtons
+    var popupButtons = Array.isArray(settings.popupControllerButtons)
+      ? settings.popupControllerButtons
       : tcDefaults.popupControllerButtons;
     populatePopupControlBarEditor(popupButtons);
     updatePopupEditorDisabledState();
@@ -1674,13 +1659,30 @@ function restore_defaults() {
     function () {}
   );
 
-  chrome.storage.sync.set(tcDefaults, function () {
-    restore_options();
-    var status = document.getElementById("status");
-    status.textContent = "Default options restored";
-    setTimeout(function () {
-      status.textContent = "";
-    }, 1000);
+  chrome.storage.sync.remove(legacySyncKeys, function () {
+    if (chrome.runtime.lastError) {
+      var errorStatus = document.getElementById("status");
+      errorStatus.textContent =
+        "Error: Failed to clear legacy settings - " +
+        chrome.runtime.lastError.message;
+      return;
+    }
+
+    persistManagedSyncSettings(tcDefaults, function (error) {
+      if (error) {
+        var errorStatus = document.getElementById("status");
+        errorStatus.textContent =
+          "Error: Failed to restore defaults - " + error.message;
+        return;
+      }
+
+      restore_options();
+      var status = document.getElementById("status");
+      status.textContent = "Default options restored";
+      setTimeout(function () {
+        status.textContent = "";
+      }, 1000);
+    });
   });
 }
 
diff --git a/popup.html b/popup.html
index 35371f3..8463d54 100644
--- a/popup.html
+++ b/popup.html
@@ -4,6 +4,7 @@
     <meta charset="utf-8" />
     <title>Speeder</title>
     <link rel="stylesheet" href="popup.css" />
+    <script src="settings-core.js"></script>
     <script src="ui-icons.js"></script>
     <script src="popup.js"></script>
   </head>
diff --git a/popup.js b/popup.js
index 76c9273..be5e1f4 100644
--- a/popup.js
+++ b/popup.js
@@ -20,49 +20,15 @@ document.addEventListener("DOMContentLoaded", function () {
 
   var defaultButtons = ["rewind", "slower", "faster", "advance", "display"];
   var popupExcludedButtonIds = new Set(["settings"]);
-  var storageDefaults = {
-    enabled: true,
-    showPopupControlBar: true,
-    controllerButtons: defaultButtons,
-    popupMatchHoverControls: true,
-    popupControllerButtons: defaultButtons,
-    siteRules: []
-  };
   var renderToken = 0;
 
-  function escapeStringRegExp(str) {
-    const m = /[|\\{}()[\]^$+*?.]/g;
-    return str.replace(m, "\\$&");
-  }
-
   function matchSiteRule(url, siteRules) {
     if (!url || !Array.isArray(siteRules)) return null;
-    for (var i = 0; i < siteRules.length; i++) {
-      var rule = siteRules[i];
-      if (!rule || !rule.pattern) continue;
-      var pattern = rule.pattern.replace(regStrip, "");
-      if (pattern.length === 0) continue;
-      var re;
-      if (pattern.startsWith("/") && pattern.lastIndexOf("/") > 0) {
-        try {
-          var ls = pattern.lastIndexOf("/");
-          re = new RegExp(pattern.substring(1, ls), pattern.substring(ls + 1));
-        } catch (e) {
-          continue;
-        }
-      } else {
-        re = new RegExp(escapeStringRegExp(pattern));
-      }
-      if (re && re.test(url)) return rule;
-    }
-    return null;
+    return vscMatchSiteRule(url, siteRules);
   }
 
   function isSiteRuleDisabled(rule) {
-    return Boolean(
-      rule &&
-      (rule.enabled === false || rule.disableExtension === true)
-    );
+    return vscIsSiteRuleDisabled(rule);
   }
 
   function resolvePopupButtons(storage, siteRule) {
@@ -230,17 +196,21 @@ document.addEventListener("DOMContentLoaded", function () {
       btn.dataset.action = btnId;
       var customEntry = customMap[btnId];
       if (customEntry && customEntry.svg) {
-        var customSpan = document.createElement("span");
-        customSpan.className = "vsc-btn-icon";
-        customSpan.innerHTML = customEntry.svg;
-        btn.appendChild(customSpan);
+        var customSpan = vscCreateSvgWrap(document, customEntry.svg, "vsc-btn-icon");
+        if (customSpan) {
+          btn.appendChild(customSpan);
+        } else {
+          btn.textContent = def.label || "?";
+        }
       } else if (typeof vscIconSvgString === "function") {
         var svgStr = vscIconSvgString(btnId, 16);
         if (svgStr) {
-          var iconSpan = document.createElement("span");
-          iconSpan.className = "vsc-btn-icon";
-          iconSpan.innerHTML = svgStr;
-          btn.appendChild(iconSpan);
+          var iconSpan = vscCreateSvgWrap(document, svgStr, "vsc-btn-icon");
+          if (iconSpan) {
+            btn.appendChild(iconSpan);
+          } else {
+            btn.textContent = def.label || "?";
+          }
         } else {
           btn.textContent = def.label || "?";
         }
@@ -330,8 +300,9 @@ document.addEventListener("DOMContentLoaded", function () {
           ? loc.customButtonIcons
           : {};
 
-      chrome.storage.sync.get(storageDefaults, function (storage) {
+      chrome.storage.sync.get(null, function (storage) {
         if (currentRenderToken !== renderToken) return;
+        storage = vscExpandStoredSettings(storage);
 
       getActiveTabContext(function (context) {
         if (currentRenderToken !== renderToken) return;
@@ -393,7 +364,9 @@ document.addEventListener("DOMContentLoaded", function () {
       changes.controllerButtons ||
       changes.popupMatchHoverControls ||
       changes.popupControllerButtons ||
-      changes.siteRules
+      changes.siteRules ||
+      changes.siteRulesMeta ||
+      changes.siteRulesFormat
     ) {
       renderForActiveTab();
     }
@@ -402,9 +375,37 @@ document.addEventListener("DOMContentLoaded", function () {
   renderForActiveTab();
 
   function toggleEnabled(enabled, callback) {
-    chrome.storage.sync.set({ enabled: enabled }, function () {
-      toggleEnabledUI(enabled);
-      if (callback) callback(enabled);
+    chrome.storage.sync.get(null, function (storage) {
+      var nextSettings = vscExpandStoredSettings(storage);
+      nextSettings.enabled = enabled;
+      var storedSettings = vscBuildStoredSettingsDiff(nextSettings);
+
+      chrome.storage.sync.remove(vscGetManagedSyncKeys(), function () {
+        if (chrome.runtime.lastError) {
+          setStatusMessage(
+            "Failed to update settings: " + chrome.runtime.lastError.message
+          );
+          return;
+        }
+
+        if (Object.keys(storedSettings).length === 0) {
+          toggleEnabledUI(enabled);
+          if (callback) callback(enabled);
+          return;
+        }
+
+        chrome.storage.sync.set(storedSettings, function () {
+          if (chrome.runtime.lastError) {
+            setStatusMessage(
+              "Failed to update settings: " + chrome.runtime.lastError.message
+            );
+            return;
+          }
+
+          toggleEnabledUI(enabled);
+          if (callback) callback(enabled);
+        });
+      });
     });
   }
 
diff --git a/settings-core.js b/settings-core.js
new file mode 100644
index 0000000..62a8195
--- /dev/null
+++ b/settings-core.js
@@ -0,0 +1,644 @@
+(function (global) {
+  "use strict";
+
+  var SITE_RULES_DIFF_FORMAT = "defaults-diff-v1";
+  var DEFAULT_BUTTONS = ["rewind", "slower", "faster", "advance", "display"];
+  var SITE_RULE_OVERRIDE_KEYS = [
+    "controllerLocation",
+    "controllerMarginTop",
+    "controllerMarginBottom",
+    "startHidden",
+    "hideWithControls",
+    "hideWithControlsTimer",
+    "rememberSpeed",
+    "forceLastSavedSpeed",
+    "audioBoolean",
+    "controllerOpacity",
+    "enableSubtitleNudge",
+    "subtitleNudgeInterval",
+    "controllerButtons",
+    "showPopupControlBar",
+    "popupControllerButtons",
+    "shortcuts",
+    "preferredSpeed"
+  ];
+  var DIFFABLE_OPTION_KEYS = [
+    "rememberSpeed",
+    "forceLastSavedSpeed",
+    "audioBoolean",
+    "enabled",
+    "startHidden",
+    "hideWithControls",
+    "hideWithControlsTimer",
+    "controllerLocation",
+    "controllerOpacity",
+    "controllerMarginTop",
+    "controllerMarginBottom",
+    "keyBindings",
+    "siteRules",
+    "siteRulesMeta",
+    "siteRulesFormat",
+    "controllerButtons",
+    "showPopupControlBar",
+    "popupMatchHoverControls",
+    "popupControllerButtons",
+    "enableSubtitleNudge",
+    "subtitleNudgeInterval",
+    "subtitleNudgeAmount"
+  ];
+  var MANAGED_SYNC_KEYS = DIFFABLE_OPTION_KEYS.concat([
+    "hideWithYouTubeControls"
+  ]);
+
+  var DEFAULT_SETTINGS = {
+    speed: 1.0,
+    lastSpeed: 1.0,
+    displayKeyCode: 86,
+    rememberSpeed: false,
+    audioBoolean: false,
+    startHidden: false,
+    hideWithYouTubeControls: false,
+    hideWithControls: false,
+    hideWithControlsTimer: 2.0,
+    controllerLocation: "top-left",
+    forceLastSavedSpeed: false,
+    enabled: true,
+    controllerOpacity: 0.3,
+    controllerMarginTop: 0,
+    controllerMarginRight: 0,
+    controllerMarginBottom: 65,
+    controllerMarginLeft: 0,
+    keyBindings: [
+      {
+        action: "display",
+        key: "V",
+        keyCode: 86,
+        code: null,
+        disabled: false,
+        value: 0,
+        force: false,
+        predefined: true
+      },
+      {
+        action: "move",
+        key: "P",
+        keyCode: 80,
+        code: null,
+        disabled: false,
+        value: 0,
+        force: false,
+        predefined: true
+      },
+      {
+        action: "slower",
+        key: "S",
+        keyCode: 83,
+        code: null,
+        disabled: false,
+        value: 0.1,
+        force: false,
+        predefined: true
+      },
+      {
+        action: "faster",
+        key: "D",
+        keyCode: 68,
+        code: null,
+        disabled: false,
+        value: 0.1,
+        force: false,
+        predefined: true
+      },
+      {
+        action: "rewind",
+        key: "Z",
+        keyCode: 90,
+        code: null,
+        disabled: false,
+        value: 10,
+        force: false,
+        predefined: true
+      },
+      {
+        action: "advance",
+        key: "X",
+        keyCode: 88,
+        code: null,
+        disabled: false,
+        value: 10,
+        force: false,
+        predefined: true
+      },
+      {
+        action: "reset",
+        key: "R",
+        keyCode: 82,
+        code: null,
+        disabled: false,
+        value: 0,
+        force: false,
+        predefined: true
+      },
+      {
+        action: "fast",
+        key: "G",
+        keyCode: 71,
+        code: null,
+        disabled: false,
+        value: 1.8,
+        force: false,
+        predefined: true
+      },
+      {
+        action: "toggleSubtitleNudge",
+        key: "N",
+        keyCode: 78,
+        code: null,
+        disabled: false,
+        value: 0,
+        force: false,
+        predefined: true
+      }
+    ],
+    siteRules: [
+      {
+        pattern: "/^https:\\/\\/(www\\.)?youtube\\.com\\/(?!shorts\\/).*/",
+        enabled: true,
+        enableSubtitleNudge: true,
+        subtitleNudgeInterval: 50
+      },
+      {
+        pattern: "/^https:\\/\\/(www\\.)?youtube\\.com\\/shorts\\/.*/",
+        enabled: true,
+        rememberSpeed: true,
+        controllerMarginTop: 60,
+        controllerMarginBottom: 85
+      }
+    ],
+    controllerButtons: DEFAULT_BUTTONS.slice(),
+    showPopupControlBar: true,
+    popupMatchHoverControls: true,
+    popupControllerButtons: DEFAULT_BUTTONS.slice(),
+    enableSubtitleNudge: false,
+    subtitleNudgeInterval: 50,
+    subtitleNudgeAmount: 0.001
+  };
+
+  function clonePlainData(value) {
+    if (value === undefined) {
+      return undefined;
+    }
+    return JSON.parse(JSON.stringify(value));
+  }
+
+  function hasOwn(obj, key) {
+    return Boolean(obj) && Object.prototype.hasOwnProperty.call(obj, key);
+  }
+
+  function isPlainObject(value) {
+    return Boolean(value) && typeof value === "object" && !Array.isArray(value);
+  }
+
+  function sortComparableValue(value) {
+    if (Array.isArray(value)) {
+      return value.map(sortComparableValue);
+    }
+
+    if (isPlainObject(value)) {
+      var sorted = {};
+      Object.keys(value)
+        .sort()
+        .forEach(function (key) {
+          if (value[key] === undefined) {
+            return;
+          }
+          sorted[key] = sortComparableValue(value[key]);
+        });
+      return sorted;
+    }
+
+    return value;
+  }
+
+  function areComparableValuesEqual(a, b) {
+    return (
+      JSON.stringify(sortComparableValue(a)) ===
+      JSON.stringify(sortComparableValue(b))
+    );
+  }
+
+  function deepMergeDefaults(defaults, overrides) {
+    if (Array.isArray(defaults)) {
+      return Array.isArray(overrides)
+        ? clonePlainData(overrides)
+        : clonePlainData(defaults);
+    }
+
+    if (isPlainObject(defaults)) {
+      var result = clonePlainData(defaults) || {};
+      if (!isPlainObject(overrides)) {
+        return result;
+      }
+
+      Object.keys(overrides).forEach(function (key) {
+        if (overrides[key] === undefined) {
+          return;
+        }
+
+        if (hasOwn(defaults, key)) {
+          result[key] = deepMergeDefaults(defaults[key], overrides[key]);
+        } else {
+          result[key] = clonePlainData(overrides[key]);
+        }
+      });
+
+      return result;
+    }
+
+    return overrides === undefined
+      ? clonePlainData(defaults)
+      : clonePlainData(overrides);
+  }
+
+  function deepDiff(current, defaults) {
+    if (current === undefined) {
+      return undefined;
+    }
+
+    if (Array.isArray(current)) {
+      return areComparableValuesEqual(current, defaults)
+        ? undefined
+        : clonePlainData(current);
+    }
+
+    if (isPlainObject(current)) {
+      var result = {};
+      Object.keys(current).forEach(function (key) {
+        var diff = deepDiff(current[key], defaults && defaults[key]);
+        if (diff !== undefined) {
+          result[key] = diff;
+        }
+      });
+      return Object.keys(result).length > 0 ? result : undefined;
+    }
+
+    return areComparableValuesEqual(current, defaults)
+      ? undefined
+      : clonePlainData(current);
+  }
+
+  function getDefaultSiteRules() {
+    return clonePlainData(DEFAULT_SETTINGS.siteRules) || [];
+  }
+
+  function getDefaultSiteRulesByPattern() {
+    var map = Object.create(null);
+    getDefaultSiteRules().forEach(function (rule) {
+      if (!rule || typeof rule.pattern !== "string" || !rule.pattern) {
+        return;
+      }
+      map[rule.pattern] = rule;
+    });
+    return map;
+  }
+
+  function normalizeSiteRuleForDiff(rule, baseSettings) {
+    if (!rule || typeof rule !== "object" || Array.isArray(rule)) {
+      return null;
+    }
+
+    var pattern = typeof rule.pattern === "string" ? rule.pattern.trim() : "";
+    if (!pattern) {
+      return null;
+    }
+
+    var normalized = { pattern: pattern };
+    var baseEnabled = hasOwn(baseSettings, "enabled")
+      ? Boolean(baseSettings.enabled)
+      : true;
+    var ruleEnabled = hasOwn(rule, "enabled")
+      ? Boolean(rule.enabled)
+      : hasOwn(rule, "disableExtension")
+        ? !Boolean(rule.disableExtension)
+        : baseEnabled;
+
+    if (!areComparableValuesEqual(ruleEnabled, baseEnabled)) {
+      normalized.enabled = ruleEnabled;
+    }
+
+    SITE_RULE_OVERRIDE_KEYS.forEach(function (key) {
+      var baseValue = clonePlainData(baseSettings[key]);
+      var effectiveValue = hasOwn(rule, key)
+        ? clonePlainData(rule[key])
+        : baseValue;
+
+      if (!areComparableValuesEqual(effectiveValue, baseValue)) {
+        normalized[key] = effectiveValue;
+      }
+    });
+
+    Object.keys(rule).forEach(function (key) {
+      if (
+        key === "pattern" ||
+        key === "enabled" ||
+        key === "disableExtension" ||
+        SITE_RULE_OVERRIDE_KEYS.indexOf(key) !== -1 ||
+        rule[key] === undefined
+      ) {
+        return;
+      }
+
+      normalized[key] = clonePlainData(rule[key]);
+    });
+
+    return normalized;
+  }
+
+  function compressSiteRules(siteRules, baseSettings) {
+    if (!Array.isArray(siteRules)) {
+      return {};
+    }
+
+    var defaultRules = getDefaultSiteRules();
+    var defaultRulesByPattern = getDefaultSiteRulesByPattern();
+    var currentPatterns = new Set();
+    var exportRules = [];
+
+    siteRules.forEach(function (rule) {
+      if (!rule || typeof rule !== "object" || Array.isArray(rule)) {
+        return;
+      }
+
+      var pattern = typeof rule.pattern === "string" ? rule.pattern.trim() : "";
+      if (pattern) {
+        currentPatterns.add(pattern);
+      }
+
+      var normalizedRule = normalizeSiteRuleForDiff(rule, baseSettings);
+      if (!normalizedRule || Object.keys(normalizedRule).length === 1) {
+        return;
+      }
+
+      var defaultRule = pattern ? defaultRulesByPattern[pattern] : null;
+      var normalizedDefaultRule = defaultRule
+        ? normalizeSiteRuleForDiff(defaultRule, baseSettings)
+        : null;
+      if (normalizedDefaultRule) {
+        if (areComparableValuesEqual(normalizedRule, normalizedDefaultRule)) {
+          return;
+        }
+
+        var defaultRuleDiff = deepDiff(normalizedRule, normalizedDefaultRule);
+        if (defaultRuleDiff && Object.keys(defaultRuleDiff).length > 0) {
+          defaultRuleDiff.pattern = pattern;
+          exportRules.push(defaultRuleDiff);
+        }
+        return;
+      }
+
+      exportRules.push(normalizedRule);
+    });
+
+    var removedDefaultPatterns = defaultRules
+      .map(function (rule) {
+        return rule && typeof rule.pattern === "string" ? rule.pattern : "";
+      })
+      .filter(function (pattern) {
+        return pattern && !currentPatterns.has(pattern);
+      });
+
+    var result = {};
+    if (exportRules.length > 0) {
+      result.siteRules = exportRules;
+      result.siteRulesFormat = SITE_RULES_DIFF_FORMAT;
+    }
+    if (removedDefaultPatterns.length > 0) {
+      result.siteRulesMeta = {
+        removedDefaultPatterns: removedDefaultPatterns
+      };
+      result.siteRulesFormat = SITE_RULES_DIFF_FORMAT;
+    }
+
+    return result;
+  }
+
+  function expandSiteRules(siteRules, siteRulesMeta) {
+    var defaultRules = getDefaultSiteRules();
+    var defaultRulesByPattern = getDefaultSiteRulesByPattern();
+    if (defaultRules.length === 0) {
+      return Array.isArray(siteRules) ? clonePlainData(siteRules) : [];
+    }
+
+    var removedDefaultPatterns = new Set(
+      siteRulesMeta && Array.isArray(siteRulesMeta.removedDefaultPatterns)
+        ? siteRulesMeta.removedDefaultPatterns
+        : []
+    );
+    var modifiedDefaultRules = Object.create(null);
+    var customRules = [];
+
+    if (Array.isArray(siteRules)) {
+      siteRules.forEach(function (rule) {
+        if (!rule || typeof rule !== "object" || Array.isArray(rule)) {
+          return;
+        }
+
+        var pattern = typeof rule.pattern === "string" ? rule.pattern.trim() : "";
+        if (
+          pattern &&
+          Object.prototype.hasOwnProperty.call(defaultRulesByPattern, pattern)
+        ) {
+          modifiedDefaultRules[pattern] = clonePlainData(rule);
+          return;
+        }
+
+        customRules.push(clonePlainData(rule));
+      });
+    }
+
+    var mergedRules = [];
+
+    defaultRules.forEach(function (rule) {
+      var pattern = rule && typeof rule.pattern === "string" ? rule.pattern : "";
+      if (!pattern || removedDefaultPatterns.has(pattern)) {
+        return;
+      }
+
+      if (modifiedDefaultRules[pattern]) {
+        mergedRules.push(
+          Object.assign(
+            {},
+            clonePlainData(rule),
+            clonePlainData(modifiedDefaultRules[pattern])
+          )
+        );
+        return;
+      }
+
+      mergedRules.push(clonePlainData(rule));
+    });
+
+    customRules.forEach(function (rule) {
+      mergedRules.push(rule);
+    });
+
+    return mergedRules;
+  }
+
+  function buildStoredSettingsDiff(currentSettings) {
+    var defaults = clonePlainData(DEFAULT_SETTINGS);
+    var normalized = deepMergeDefaults(defaults, currentSettings || {});
+    var siteRuleData = compressSiteRules(normalized.siteRules, normalized);
+    var diffDefaults = {};
+    var diff = {};
+
+    delete normalized.siteRules;
+    delete normalized.siteRulesMeta;
+    delete normalized.siteRulesFormat;
+    delete normalized.hideWithYouTubeControls;
+
+    if (siteRuleData.siteRules) {
+      normalized.siteRules = siteRuleData.siteRules;
+    }
+    if (siteRuleData.siteRulesMeta) {
+      normalized.siteRulesMeta = siteRuleData.siteRulesMeta;
+    }
+    if (siteRuleData.siteRulesFormat) {
+      normalized.siteRulesFormat = siteRuleData.siteRulesFormat;
+    }
+
+    DIFFABLE_OPTION_KEYS.forEach(function (key) {
+      if (hasOwn(DEFAULT_SETTINGS, key)) {
+        diffDefaults[key] = clonePlainData(DEFAULT_SETTINGS[key]);
+      }
+      if (!hasOwn(normalized, key)) {
+        return;
+      }
+      var valueDiff = deepDiff(normalized[key], diffDefaults[key]);
+      if (valueDiff !== undefined) {
+        diff[key] = valueDiff;
+      }
+    });
+
+    return diff;
+  }
+
+  function expandStoredSettings(storage) {
+    var raw = clonePlainData(storage) || {};
+    var expanded = deepMergeDefaults(DEFAULT_SETTINGS, raw);
+
+    if (
+      !hasOwn(raw, "hideWithControls") &&
+      hasOwn(raw, "hideWithYouTubeControls")
+    ) {
+      expanded.hideWithControls = Boolean(raw.hideWithYouTubeControls);
+    }
+    expanded.hideWithYouTubeControls = expanded.hideWithControls;
+
+    if (raw.siteRulesFormat === SITE_RULES_DIFF_FORMAT) {
+      expanded.siteRules = expandSiteRules(raw.siteRules, raw.siteRulesMeta);
+    } else if (Array.isArray(raw.siteRules)) {
+      expanded.siteRules = clonePlainData(raw.siteRules);
+    } else {
+      expanded.siteRules = getDefaultSiteRules();
+    }
+
+    return expanded;
+  }
+
+  function escapeStringRegExp(str) {
+    var matcher = /[|\\{}()[\]^$+*?.]/g;
+    return String(str).replace(matcher, "\\$&");
+  }
+
+  function siteRuleMatchesUrl(rule, currentUrl) {
+    if (!rule || !rule.pattern || !currentUrl) {
+      return false;
+    }
+
+    var pattern = String(rule.pattern).trim();
+    if (!pattern) {
+      return false;
+    }
+
+    var regex;
+    if (pattern.startsWith("/") && pattern.lastIndexOf("/") > 0) {
+      try {
+        var lastSlash = pattern.lastIndexOf("/");
+        regex = new RegExp(
+          pattern.substring(1, lastSlash),
+          pattern.substring(lastSlash + 1)
+        );
+      } catch (_error) {
+        return false;
+      }
+    } else {
+      regex = new RegExp(escapeStringRegExp(pattern));
+    }
+
+    return Boolean(regex && regex.test(currentUrl));
+  }
+
+  function mergeMatchingSiteRules(currentUrl, siteRules) {
+    if (!currentUrl || !Array.isArray(siteRules)) {
+      return null;
+    }
+
+    var matchedRules = [];
+    for (var i = 0; i < siteRules.length; i++) {
+      if (siteRuleMatchesUrl(siteRules[i], currentUrl)) {
+        matchedRules.push(siteRules[i]);
+      }
+    }
+
+    if (!matchedRules.length) {
+      return null;
+    }
+
+    var mergedRule = {};
+    matchedRules.forEach(function (rule) {
+      Object.keys(rule).forEach(function (key) {
+        var value = rule[key];
+        if (Array.isArray(value)) {
+          mergedRule[key] = clonePlainData(value);
+          return;
+        }
+        if (isPlainObject(value)) {
+          mergedRule[key] = clonePlainData(value);
+          return;
+        }
+        mergedRule[key] = value;
+      });
+    });
+
+    return mergedRule;
+  }
+
+  function isSiteRuleDisabled(rule) {
+    return Boolean(
+      rule &&
+      (
+        rule.enabled === false ||
+        (typeof rule.enabled === "undefined" && rule.disableExtension === true)
+      )
+    );
+  }
+
+  global.vscClonePlainData = clonePlainData;
+  global.vscAreComparableValuesEqual = areComparableValuesEqual;
+  global.vscDeepMergeDefaults = deepMergeDefaults;
+  global.vscBuildStoredSettingsDiff = buildStoredSettingsDiff;
+  global.vscExpandStoredSettings = expandStoredSettings;
+  global.vscGetSettingsDefaults = function () {
+    return clonePlainData(DEFAULT_SETTINGS);
+  };
+  global.vscGetManagedSyncKeys = function () {
+    return MANAGED_SYNC_KEYS.slice();
+  };
+  global.vscGetSiteRulesDiffFormat = function () {
+    return SITE_RULES_DIFF_FORMAT;
+  };
+  global.vscMatchSiteRule = mergeMatchingSiteRules;
+  global.vscSiteRuleMatchesUrl = siteRuleMatchesUrl;
+  global.vscIsSiteRuleDisabled = isSiteRuleDisabled;
+})(typeof globalThis !== "undefined" ? globalThis : this);
diff --git a/ui-icons.js b/ui-icons.js
index 631cd9e..63ddf1a 100644
--- a/ui-icons.js
+++ b/ui-icons.js
@@ -3,6 +3,7 @@
  * Use stroke="currentColor" so buttons inherit foreground for monochrome UI.
  */
 var VSC_ICON_SIZE_DEFAULT = 18;
+var VSC_SVG_NS = "http://www.w3.org/2000/svg";
 
 /** Inner SVG markup only (paths / shapes inside <svg>). */
 var vscUiIconPaths = {
@@ -54,6 +55,79 @@ function vscIconSvgString(action, size) {
   );
 }
 
+function vscClearElement(el) {
+  if (!el) return;
+  while (el.firstChild) {
+    el.removeChild(el.firstChild);
+  }
+}
+
+function vscSanitizeSvgTree(svg) {
+  if (!svg || String(svg.tagName).toLowerCase() !== "svg") return null;
+
+  svg.querySelectorAll("script, style, foreignObject").forEach(function (n) {
+    n.remove();
+  });
+
+  svg.querySelectorAll("*").forEach(function (el) {
+    for (var i = el.attributes.length - 1; i >= 0; i--) {
+      var attr = el.attributes[i];
+      var name = attr.name.toLowerCase();
+      var val = attr.value;
+      if (name.indexOf("on") === 0) {
+        el.removeAttribute(attr.name);
+        continue;
+      }
+      if (
+        (name === "href" || name === "xlink:href") &&
+        /^\s*javascript:/i.test(val)
+      ) {
+        el.removeAttribute(attr.name);
+      }
+    }
+  });
+
+  svg.setAttribute("xmlns", VSC_SVG_NS);
+  svg.setAttribute("aria-hidden", "true");
+  return svg;
+}
+
+function vscCreateSvgNode(doc, svgText) {
+  if (!doc || !svgText || typeof svgText !== "string") return null;
+  var clean = String(svgText).replace(/\0/g, "").trim();
+  if (!clean || !/<svg[\s>]/i.test(clean)) return null;
+
+  var parsed = new DOMParser().parseFromString(clean, "image/svg+xml");
+  if (parsed.querySelector("parsererror")) return null;
+
+  var svg = vscSanitizeSvgTree(parsed.querySelector("svg"));
+  if (!svg) return null;
+
+  return doc.importNode(svg, true);
+}
+
+function vscSetSvgContent(el, svgText) {
+  if (!el) return false;
+  vscClearElement(el);
+
+  var doc = el.ownerDocument || document;
+  var svg = vscCreateSvgNode(doc, svgText);
+  if (!svg) return false;
+
+  el.appendChild(svg);
+  return true;
+}
+
+function vscCreateSvgWrap(doc, svgText, className) {
+  if (!doc) return null;
+  var span = doc.createElement("span");
+  span.className = className || "vsc-btn-icon";
+  if (!vscSetSvgContent(span, svgText)) {
+    return null;
+  }
+  return span;
+}
+
 /**
  * @param {Document} doc
  * @param {string} action
@@ -62,8 +136,5 @@ function vscIconSvgString(action, size) {
 function vscIconWrap(doc, action, size) {
   var html = vscIconSvgString(action, size);
   if (!html) return null;
-  var span = doc.createElement("span");
-  span.className = "vsc-btn-icon";
-  span.innerHTML = html;
-  return span;
+  return vscCreateSvgWrap(doc, html, "vsc-btn-icon");
 }