Fix css mismatch after koreader sync

lib/Epub/Epub/Section.cpp

@@ -60,7 +60,7 @@ constexpr uint32_t FNV_OFFSET_BASIS = 0x811C9DC5;  // 2166136261
 #endif
 
 #ifndef SCT_EMBEDDED_STYLE_MIN_CONTIG_HEAP_BYTES
-#define SCT_EMBEDDED_STYLE_MIN_CONTIG_HEAP_BYTES (56 * 1024)
+#define SCT_EMBEDDED_STYLE_MIN_CONTIG_HEAP_BYTES (36 * 1024)
 #endif
 
 constexpr uint32_t EMBEDDED_STYLE_MIN_FREE_HEAP_BYTES = SCT_EMBEDDED_STYLE_MIN_FREE_HEAP_BYTES;
@@ -244,6 +244,7 @@ bool Section::loadSectionFile(const int fontId, const float lineCompression, con
                               const uint16_t viewportHeight, const bool hyphenationEnabled, const bool embeddedStyle,
                               const bool bionicReadingEnabled, const uint8_t imageRendering) {
   truncatedCache = false;
+  embeddedStyleFallback = false;
   uint32_t propertyHash =
       calculatePropertyHash(fontId, lineCompression, extraParagraphSpacing, paragraphAlignment, viewportWidth,
                             viewportHeight, hyphenationEnabled, embeddedStyle, bionicReadingEnabled, imageRendering);
@@ -260,6 +261,7 @@ bool Section::loadSectionFile(const int fontId, const float lineCompression, con
       if (Storage.openFileForRead("SCT", fallbackPath, file)) {
         filePath = fallbackPath;
         usingEmbeddedStyleFallback = true;
+        embeddedStyleFallback = true;
         LOG_INF("SCT", "Using no-CSS section cache fallback: %s", filePath.c_str());
       } else {
         return false;
@@ -419,6 +421,13 @@ bool Section::createSectionFile(const int fontId, const float lineCompression, c
     return false;
   }
 
+  // Reset build state — createSectionFile may be called on a Section that previously
+  // loaded a cache (e.g. fallback no-CSS file). pageCount must start at 0 so that
+  // onPageComplete() numbering and paragraphLutPerPage stay in lockstep.
+  file.close();
+  pageCount = 0;
+  this->lut.clear();
+
   if (!Storage.openFileForWrite("SCT", filePath, file)) {
     return false;
   }

lib/Epub/Epub/Section.h

@@ -18,6 +18,7 @@ class Section {
   FsFile file;
   std::vector<uint32_t> lut;  // Cached page byte-offsets; loaded once, avoids per-page LUT seek
   bool truncatedCache = false;
+  bool embeddedStyleFallback = false;
 
   void writeSectionFileHeader(int fontId, float lineCompression, bool extraParagraphSpacing, uint8_t paragraphAlignment,
                               uint16_t viewportWidth, uint16_t viewportHeight, bool hyphenationEnabled,
@@ -70,6 +71,7 @@ class Section {
                          const std::function<void(int)>& progressFn = nullptr, bool skipEviction = false);
   std::unique_ptr<Page> loadPageFromSectionFile();
   bool isTruncatedCache() const { return truncatedCache; }
+  bool isEmbeddedStyleFallback() const { return embeddedStyleFallback; }
 
   // Given a page in this section, return the TOC index for that page.
   int getTocIndexForPage(int page) const;

src/activities/reader/EpubReaderActivity.cpp

@@ -1604,6 +1604,30 @@ void EpubReaderActivity::render(RenderLock&& lock) {
         section.reset();
         return;
       }
+    } else if (section->isEmbeddedStyleFallback()) {
+      LOG_INF("ERS", "No-CSS fallback loaded; rebuilding with embedded CSS...");
+      lastRenderStats.cacheRebuilt = true;
+
+      Rect popupRect{};
+      const auto progressFn = [this, &popupRect](int progress) {
+        if (popupRect.width == 0) {
+          popupRect = GUI.drawPopup(renderer, tr(STR_INDEXING));
+          return;
+        }
+        GUI.fillPopupProgress(renderer, popupRect, progress);
+      };
+
+      renderer.clearSdCardFontAccumulation();
+      if (!section->createSectionFile(getEffectiveReaderFontId(), getEffectiveReaderLineCompression(),
+                                      SETTINGS.extraParagraphSpacing, getEffectiveParagraphAlignment(), viewportWidth,
+                                      viewportHeight, SETTINGS.hyphenationEnabled, embeddedStyle,
+                                      bookBionicReadingOverride, imageRendering, progressFn)) {
+        LOG_ERR("ERS", "Failed to rebuild CSS section cache; keeping fallback");
+        section->loadSectionFile(getEffectiveReaderFontId(), getEffectiveReaderLineCompression(),
+                                 SETTINGS.extraParagraphSpacing, getEffectiveParagraphAlignment(), viewportWidth,
+                                 viewportHeight, SETTINGS.hyphenationEnabled, embeddedStyle, bookBionicReadingOverride,
+                                 imageRendering);
+      }
     } else {
       LOG_DBG("ERS", "Cache found, skipping build...");
     }