diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 2897ed0dbd..d73aac1d4b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -132,7 +132,7 @@ jobs:
         uses: actions/cache@v4
         with:
           path: build/test/_deps/googletest-src
-          key: ${{ runner.os }}-googletest-v1.15.2
+          key: ${{ runner.os }}-googletest-${{ hashFiles('test/CMakeLists.txt') }}
 
       - name: Configure
         run: cmake -S test -B build/test -G Ninja -DCMAKE_BUILD_TYPE=Release
diff --git a/lib/Epub/Epub.cpp b/lib/Epub/Epub.cpp
index 2a0d0a2e5a..3e2fb827dd 100644
--- a/lib/Epub/Epub.cpp
+++ b/lib/Epub/Epub.cpp
@@ -256,6 +256,38 @@ bool Epub::parseTocNavFile() const {
   return true;
 }
 
+void Epub::discoverCssFilesFromZip() {
+  if (!bookMetadataCache || !bookMetadataCache->isLoaded()) {
+    LOG_ERR("EBP", "Cannot discover CSS from ZIP because book metadata cache is not loaded");
+    return;
+  }
+
+  ZipFile zf(filepath);
+
+  if (!zf.loadAllFileStatSlims()) {
+    LOG_ERR("EBP", "Failed to load ZIP file stat slims for CSS discovery");
+    return;
+  }
+
+  size_t lastSlash = contentBasePath.find_last_of('/');
+
+  std::string opfDir = (lastSlash != std::string::npos) ? contentBasePath.substr(0, lastSlash + 1) : "";
+
+  zf.enumerateFilePaths([&](std::string_view filePath) {
+    if (!opfDir.empty() && filePath.find(opfDir) != 0) {
+      return;  // Skip files that are not in the same directory as OPF manifest, as CSS files are typically located
+               // there or in subfolders
+    }
+
+    if (FsHelpers::hasCssExtension(filePath)) {
+      if (std::find(cssFiles.begin(), cssFiles.end(), filePath) == cssFiles.end()) {
+        LOG_DBG("EBP", "Discovered CSS file via ZIP enumeration: %.*s", (int)filePath.size(), filePath.data());
+        cssFiles.push_back(std::string{filePath});
+      }
+    }
+  });
+}
+
 void Epub::parseCssFiles() const {
   // Maximum CSS file size we'll attempt to parse (uncompressed)
   // Larger files risk memory exhaustion on ESP32
@@ -330,9 +362,9 @@ void Epub::parseCssFiles() const {
   if (!cssParser->saveToCache()) {
     LOG_ERR("EBP", "Failed to save CSS rules to cache");
   }
-  cssParser->clear();
 
   LOG_DBG("EBP", "Loaded %zu CSS style rules from %zu files", cssParser->ruleCount(), cssFiles.size());
+  cssParser->clear();
 }
 
 // load in the meta data for the epub file
@@ -355,6 +387,10 @@ bool Epub::load(const bool buildIfMissing, const bool skipLoadingCss) {
         if (!parseContentOpf(bookMetadataCache->coreMetadata)) {
           LOG_ERR("EBP", "Could not parse content.opf from cached bookMetadata for CSS files");
           // continue anyway - book will work without CSS and we'll still load any inline style CSS
+        } else {
+          // Handle case where CSS files are not listed in OPF manifest
+          // but are still referenced by HTML files - discover and parse them too
+          discoverCssFilesFromZip();
         }
         parseCssFiles();
         // Invalidate section caches so they are rebuilt with the new CSS
@@ -458,6 +494,9 @@ bool Epub::load(const bool buildIfMissing, const bool skipLoadingCss) {
   }
 
   if (!skipLoadingCss) {
+    // Handle case where CSS files are not listed in OPF manifest
+    // but are still referenced by HTML files - discover and parse them too
+    discoverCssFilesFromZip();
     // Parse CSS files after cache reload
     parseCssFiles();
     Storage.removeDir((cachePath + "/sections").c_str());
diff --git a/lib/Epub/Epub.h b/lib/Epub/Epub.h
index ba1dbba7e9..da165e7db7 100644
--- a/lib/Epub/Epub.h
+++ b/lib/Epub/Epub.h
@@ -37,6 +37,7 @@ class Epub {
   bool parseTocNcxFile() const;
   bool parseTocNavFile() const;
   void parseCssFiles() const;
+  void discoverCssFilesFromZip();
 
  public:
   explicit Epub(std::string filepath, const std::string& cacheDir) : filepath(std::move(filepath)) {
diff --git a/lib/FsHelpers/FsHelpers.cpp b/lib/FsHelpers/FsHelpers.cpp
index a73f890104..fe48587f16 100644
--- a/lib/FsHelpers/FsHelpers.cpp
+++ b/lib/FsHelpers/FsHelpers.cpp
@@ -129,6 +129,8 @@ bool hasTxtExtension(std::string_view fileName) { return checkFileExtension(file
 
 bool hasMarkdownExtension(std::string_view fileName) { return checkFileExtension(fileName, ".md"); }
 
+bool hasCssExtension(std::string_view fileName) { return checkFileExtension(fileName, ".css"); }
+
 std::string extractFolderPath(const std::string& filePath) {
   const auto lastSlash = filePath.find_last_of('/');
   if (lastSlash == std::string::npos || lastSlash == 0) {
diff --git a/lib/FsHelpers/FsHelpers.h b/lib/FsHelpers/FsHelpers.h
index 8edc30343d..8dfbdec641 100644
--- a/lib/FsHelpers/FsHelpers.h
+++ b/lib/FsHelpers/FsHelpers.h
@@ -39,6 +39,9 @@ bool hasTxtExtension(std::string_view fileName);
 // Check for .md extension (case-insensitive)
 bool hasMarkdownExtension(std::string_view fileName);
 
+// Check for .css extension (case-insensitive)
+bool hasCssExtension(std::string_view fileName);
+
 std::string extractFolderPath(const std::string& filePath);
 
 /**
diff --git a/lib/ZipFile/ZipFile.h b/lib/ZipFile/ZipFile.h
index 2a32e974e1..6c4f93961b 100644
--- a/lib/ZipFile/ZipFile.h
+++ b/lib/ZipFile/ZipFile.h
@@ -3,6 +3,7 @@
 
 #include <deque>
 #include <string>
+#include <string_view>
 #include <unordered_map>
 
 class ZipFile {
@@ -69,4 +70,11 @@ class ZipFile {
   // These functions will open and close the zip as needed
   uint8_t* readFileToMemory(const char* filename, size_t* size = nullptr, bool trailingNullByte = false);
   bool readFileToStream(const char* filename, Print& out, size_t chunkSize);
+
+  template <typename F>
+  void enumerateFilePaths(F&& callback) const {
+    for (const auto& entry : fileStatSlimCache) {
+      callback(std::string_view{entry.first});
+    }
+  }
 };
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 577c8e5461..8e491db541 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -14,7 +14,7 @@ include(FetchContent)
 FetchContent_Declare(
   googletest
   GIT_REPOSITORY https://github.com/google/googletest.git
-  GIT_TAG v1.15.2
+  GIT_TAG v1.17.0
 )
 
 set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
diff --git a/test/README b/test/README
index f9856e1eff..2317a3aa9b 100644
--- a/test/README
+++ b/test/README
@@ -3,6 +3,7 @@ Host-side gtest unit tests for crosspoint-reader.
 Build and run:
 
   cmake -S test -B build/test
+  cmake --build build/test
   ctest --test-dir build/test --output-on-failure -j
 
 Run a single suite directly:
@@ -10,5 +11,5 @@ Run a single suite directly:
   cmake --build build/test --target StreamingJsonParserTest
   build/test/streaming_json_parser/StreamingJsonParserTest --gtest_filter='*'
 
-Google Test is fetched via CMake FetchContent (pinned to v1.15.2 in
-test/CMakeLists.txt) on first configure.
+Google Test is fetched via CMake FetchContent on first configure; the pinned
+version lives in test/CMakeLists.txt.
diff --git a/test/differential_rounding/DifferentialRoundingTest.cpp b/test/differential_rounding/DifferentialRoundingTest.cpp
index 275a023e2c..9efed6a84c 100644
--- a/test/differential_rounding/DifferentialRoundingTest.cpp
+++ b/test/differential_rounding/DifferentialRoundingTest.cpp
@@ -177,10 +177,10 @@ TEST(EpdFont, KernLookup) {
 }
 
 TEST(EpdFont, GlyphLookup) {
-  EXPECT_NE(testFont().getGlyph('T'), nullptr);
-  EXPECT_NE(testFont().getGlyph('a'), nullptr);
-  EXPECT_NE(testFont().getGlyph('o'), nullptr);
-  EXPECT_NE(testFont().getGlyph('x'), nullptr);
+  ASSERT_NE(testFont().getGlyph('T'), nullptr);
+  ASSERT_NE(testFont().getGlyph('a'), nullptr);
+  ASSERT_NE(testFont().getGlyph('o'), nullptr);
+  ASSERT_NE(testFont().getGlyph('x'), nullptr);
   EXPECT_EQ(testFont().getGlyph('T')->advanceX, 137);
   EXPECT_EQ(testFont().getGlyph('a')->advanceX, 130);
   EXPECT_EQ(testFont().getGlyph('o')->advanceX, 145);
diff --git a/test/release_json_parser/ReleaseJsonParserTest.cpp b/test/release_json_parser/ReleaseJsonParserTest.cpp
index b8ba4c856f..babe5c764b 100644
--- a/test/release_json_parser/ReleaseJsonParserTest.cpp
+++ b/test/release_json_parser/ReleaseJsonParserTest.cpp
@@ -151,6 +151,11 @@ TEST(ReleaseJsonParser, PrettyAndMinifiedAgree) {
   ReleaseJsonParser minified;
   minified.feed(kRealisticMinified, strlen(kRealisticMinified));
 
+  ASSERT_TRUE(pretty.foundTag());
+  ASSERT_TRUE(pretty.foundFirmware());
+  ASSERT_TRUE(minified.foundTag());
+  ASSERT_TRUE(minified.foundFirmware());
+
   EXPECT_STREQ(pretty.getTagName(), minified.getTagName());
   EXPECT_STREQ(pretty.getFirmwareUrl(), minified.getFirmwareUrl());
   EXPECT_EQ(pretty.getFirmwareSize(), minified.getFirmwareSize());
@@ -282,6 +287,8 @@ TEST(ReleaseJsonParser, ChunkedFeedingVariousChunkSizes) {
     EXPECT_TRUE(p.foundTag()) << "chunkSize=" << chunkSize;
     EXPECT_TRUE(p.foundFirmware()) << "chunkSize=" << chunkSize;
     EXPECT_STREQ(p.getTagName(), "v2.4.1") << "chunkSize=" << chunkSize;
+    EXPECT_STREQ(p.getFirmwareUrl(), "https://github.com/znelson/lightpoint/releases/download/v2.4.1/firmware.bin")
+        << "chunkSize=" << chunkSize;
     EXPECT_EQ(p.getFirmwareSize(), 1572864u) << "chunkSize=" << chunkSize;
   }
 }
diff --git a/test/streaming_json_parser/StreamingJsonParserTest.cpp b/test/streaming_json_parser/StreamingJsonParserTest.cpp
index d77605d474..0c1aba8083 100644
--- a/test/streaming_json_parser/StreamingJsonParserTest.cpp
+++ b/test/streaming_json_parser/StreamingJsonParserTest.cpp
@@ -154,7 +154,7 @@ TEST(StreamingJsonParser, UnicodeEscapeAscii) {
   // \u escapes for ASCII codepoints (1-byte UTF-8) decode to the raw bytes.
   auto events = parse(R"({"u": "\u0041\u0042"})");
 
-  ASSERT_GE(events.size(), 3u);
+  ASSERT_EQ(events.size(), 4u);
   EXPECT_EQ(events[2].type, EventType::STRING);
   EXPECT_EQ(events[2].value, "AB");
 }
@@ -163,7 +163,7 @@ TEST(StreamingJsonParser, UnicodeEscapeTwoByteUtf8) {
   // U+00E9 (e-acute) decodes to the 2-byte UTF-8 sequence C3 A9.
   auto events = parse(R"({"k": "caf\u00E9"})");
 
-  ASSERT_GE(events.size(), 3u);
+  ASSERT_EQ(events.size(), 4u);
   EXPECT_EQ(events[2].type, EventType::STRING);
   EXPECT_EQ(events[2].value, std::string("caf\xC3\xA9"));
 }
@@ -172,7 +172,7 @@ TEST(StreamingJsonParser, UnicodeEscapeThreeByteUtf8) {
   // U+20AC (euro sign) decodes to the 3-byte UTF-8 sequence E2 82 AC.
   auto events = parse(R"({"k": "\u20AC"})");
 
-  ASSERT_GE(events.size(), 3u);
+  ASSERT_EQ(events.size(), 4u);
   EXPECT_EQ(events[2].type, EventType::STRING);
   EXPECT_EQ(events[2].value, std::string("\xE2\x82\xAC"));
 }
@@ -181,7 +181,7 @@ TEST(StreamingJsonParser, UnicodeEscapeMixedHexCase) {
   // Lower and upper case hex digits must both decode.
   auto events = parse(R"({"k": "\u00e9\u00E9"})");
 
-  ASSERT_GE(events.size(), 3u);
+  ASSERT_EQ(events.size(), 4u);
   EXPECT_EQ(events[2].type, EventType::STRING);
   EXPECT_EQ(events[2].value, std::string("\xC3\xA9\xC3\xA9"));
 }
@@ -190,7 +190,7 @@ TEST(StreamingJsonParser, UnicodeEscapeSurrogateBecomesReplacement) {
   // Bare surrogate values (no pair handling) emit U+FFFD (EF BF BD).
   auto events = parse(R"({"k": "\uD800"})");
 
-  ASSERT_GE(events.size(), 3u);
+  ASSERT_EQ(events.size(), 4u);
   EXPECT_EQ(events[2].type, EventType::STRING);
   EXPECT_EQ(events[2].value, std::string("\xEF\xBF\xBD"));
 }
@@ -200,7 +200,7 @@ TEST(StreamingJsonParser, UnicodeEscapeInvalidHexBecomesReplacement) {
   // reprocessed as a normal string char so the rest of the string parses.
   auto events = parse(R"({"k": "\u00ZZok"})");
 
-  ASSERT_GE(events.size(), 3u);
+  ASSERT_EQ(events.size(), 4u);
   EXPECT_EQ(events[2].type, EventType::STRING);
   EXPECT_EQ(events[2].value, std::string("\xEF\xBF\xBD"
                                          "ZZok"));
@@ -209,7 +209,7 @@ TEST(StreamingJsonParser, UnicodeEscapeInvalidHexBecomesReplacement) {
 TEST(StreamingJsonParser, UnicodeEscapeMixedWithLiterals) {
   auto events = parse(R"({"k": "a\u00E9b"})");
 
-  ASSERT_GE(events.size(), 3u);
+  ASSERT_EQ(events.size(), 4u);
   EXPECT_EQ(events[2].type, EventType::STRING);
   EXPECT_EQ(events[2].value, std::string("a\xC3\xA9"
                                          "b"));
@@ -247,7 +247,7 @@ TEST(StreamingJsonParser, UnicodeEscapeSplitAcrossChunks) {
 TEST(StreamingJsonParser, Numbers) {
   auto events = parse(R"({"int": 42, "neg": -7, "flt": 3.14, "exp": 1e10, "nexp": -2.5E-3})");
 
-  ASSERT_GE(events.size(), 11u);
+  ASSERT_EQ(events.size(), 12u);
   EXPECT_EQ(events[2].type, EventType::NUMBER);
   EXPECT_EQ(events[2].value, "42");
   EXPECT_EQ(events[4].type, EventType::NUMBER);
@@ -263,7 +263,7 @@ TEST(StreamingJsonParser, Numbers) {
 TEST(StreamingJsonParser, BooleansAndNull) {
   auto events = parse(R"({"t": true, "f": false, "n": null})");
 
-  ASSERT_GE(events.size(), 7u);
+  ASSERT_EQ(events.size(), 8u);
   EXPECT_EQ(events[2].type, EventType::BOOL_TRUE);
   EXPECT_EQ(events[4].type, EventType::BOOL_FALSE);
   EXPECT_EQ(events[6].type, EventType::NULL_VAL);
@@ -454,7 +454,7 @@ TEST(StreamingJsonParser, TruncatedInputNoCrash) {
 
 TEST(StreamingJsonParser, AllEscapeSequences) {
   auto events = parse(R"({"e": "\b\f\n\r\t\"\\\/"})");
-  ASSERT_GE(events.size(), 3u);
+  ASSERT_EQ(events.size(), 4u);
   EXPECT_EQ(events[2].type, EventType::STRING);
   EXPECT_EQ(events[2].value, std::string("\b\f\n\r\t\"\\/"));
 }
@@ -509,7 +509,7 @@ TEST(StreamingJsonParser, NestingOverflow) {
 
 TEST(StreamingJsonParser, NumberZero) {
   auto events = parse(R"({"z": 0})");
-  ASSERT_GE(events.size(), 3u);
+  ASSERT_EQ(events.size(), 4u);
   EXPECT_EQ(events[2].type, EventType::NUMBER);
   EXPECT_EQ(events[2].value, "0");
 }