feat: persist inheritance lock state per element via data attribute

- Store unlock state in data-inheritance-unlocked attribute on DOM element
- Each element/page now remembers its own inheritance state
- Re-locking removes element-specific CSS block to restore inheritance
- Elements revert to general styles from TextSettings/PageSettings

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/components/ElementPopup.vue

@@ -369,6 +369,22 @@ const elementCss = computed(() => {
   return stylesheetStore.extractBlock(selector.value) || '';
 });
 
+// Remove the element-specific CSS block to restore inheritance
+const removeElementBlock = () => {
+  if (!selector.value) return;
+
+  const block = stylesheetStore.extractBlock(selector.value);
+  if (block) {
+    // Escape special regex characters in selector
+    const escaped = selector.value.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
+    // Remove the block and any surrounding whitespace
+    stylesheetStore.content = stylesheetStore.content.replace(
+      new RegExp(`\\n?${escaped}\\s*\\{[^}]*\\}\\n?`),
+      '\n'
+    );
+  }
+};
+
 const highlightedCss = computed(() => {
   if (!elementCss.value) return '';
   return hljs.highlight(elementCss.value, { language: 'css' }).value;
@@ -601,6 +617,9 @@ const open = (element, event, count = null) => {
   // Store instance count if provided, otherwise calculate it
   elementInstanceCount.value = count !== null ? count : getInstanceCount(selector.value);
 
+  // Read inheritance state from element's data attribute
+  inheritanceLocked.value = element.dataset.inheritanceUnlocked !== 'true';
+
   // Load values from stylesheet
   loadValuesFromStylesheet();
 
@@ -664,8 +683,22 @@ const handleIframeClick = (event, targetElement = null, elementCount = null) =>
 };
 
 const toggleInheritance = () => {
+  const wasLocked = inheritanceLocked.value;
   inheritanceLocked.value = !inheritanceLocked.value;
-  // TODO: Implement CSS priority logic when unlocked
+
+  // Store the inheritance state in the element's data attribute
+  if (selectedElement.value) {
+    if (inheritanceLocked.value) {
+      delete selectedElement.value.dataset.inheritanceUnlocked;
+    } else {
+      selectedElement.value.dataset.inheritanceUnlocked = 'true';
+    }
+  }
+
+  // When re-locking, remove the element-specific CSS block to restore inheritance
+  if (inheritanceLocked.value && !wasLocked) {
+    removeElementBlock();
+  }
 };
 
 defineExpose({ handleIframeClick, close, visible });

src/components/PagePopup.vue

@@ -532,8 +532,8 @@ const open = (pageElement, event, count = 1) => {
   // Extract template name from data-page-type attribute
   templateName.value = pageElement.getAttribute('data-page-type') || '';
 
-  // Reset inheritance state when opening
-  inheritanceLocked.value = true;
+  // Read inheritance state from page element's data attribute
+  inheritanceLocked.value = pageElement.dataset.inheritanceUnlocked !== 'true';
 
   // Load values from stylesheet (@page block)
   loadValuesFromStylesheet();
@@ -583,6 +583,15 @@ const toggleInheritance = () => {
   const wasLocked = inheritanceLocked.value;
   inheritanceLocked.value = !inheritanceLocked.value;
 
+  // Store the inheritance state in the page element's data attribute
+  if (selectedPageElement.value) {
+    if (inheritanceLocked.value) {
+      delete selectedPageElement.value.dataset.inheritanceUnlocked;
+    } else {
+      selectedPageElement.value.dataset.inheritanceUnlocked = 'true';
+    }
+  }
+
   if (inheritanceLocked.value && !wasLocked) {
     // Re-locking: remove the template-specific block
     // Fields keep their values, but preview returns to @page defaults