diff --git a/phpunit.xml b/phpunit.xml
index fefddce..40f4d33 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -35,6 +35,7 @@
             <file>./tests/AppCorsMiddlewareTest.php</file>
             <file>./tests/CronExpressionTest.php</file>
             <file>./tests/ScheduleTest.php</file>
+            <file>./tests/ViteTest.php</file>
 
         </testsuite>
     </testsuites>
diff --git a/src/Vite.php b/src/Vite.php
index 6adac56..ce0d9de 100644
--- a/src/Vite.php
+++ b/src/Vite.php
@@ -166,15 +166,16 @@ protected function renderProductionTags(string $entryPoint): string
         $output = '';
         $assetUrlPrefix = $this->getAssetUrlPrefix();
 
-        // 1. CSS files (if styles are extracted)
-        if (isset($entryData['css']) && is_array($entryData['css'])) {
-            foreach ($entryData['css'] as $cssFile) {
-                $output .= sprintf(
-                    '<link rel="stylesheet" href="%s%s">' . PHP_EOL,
-                    $assetUrlPrefix,
-                    $cssFile
-                );
-            }
+        // 1. CSS files, including CSS pulled in transitively through
+        // imported chunks (Rollup can fold a CSS-only entry into a shared
+        // chunk that a sibling entry merely "imports" rather than owning a
+        // direct "css" key of its own).
+        foreach ($this->collectCss($manifest, $entryPoint) as $cssFile) {
+            $output .= sprintf(
+                '<link rel="stylesheet" href="%s%s">' . PHP_EOL,
+                $assetUrlPrefix,
+                $cssFile
+            );
         }
 
         // 2. Main JS file
@@ -189,6 +190,42 @@ protected function renderProductionTags(string $entryPoint): string
         return $output;
     }
 
+    /**
+     * Recursively collect the CSS files owned by a manifest chunk and by
+     * every chunk it imports, deduplicated and in discovery order.
+     *
+     * @param array $manifest The decoded manifest.json
+     * @param string $chunkKey The manifest key to start from
+     * @param array $visited Keys already visited, to guard against cycles
+     * @return string[] Deduplicated list of CSS file paths
+     */
+    protected function collectCss(array $manifest, string $chunkKey, array &$visited = []): array
+    {
+        if (isset($visited[$chunkKey]) || !isset($manifest[$chunkKey])) {
+            return [];
+        }
+        $visited[$chunkKey] = true;
+
+        $chunk = $manifest[$chunkKey];
+        $css = [];
+
+        if (isset($chunk['css']) && is_array($chunk['css'])) {
+            foreach ($chunk['css'] as $cssFile) {
+                $css[$cssFile] = true;
+            }
+        }
+
+        if (isset($chunk['imports']) && is_array($chunk['imports'])) {
+            foreach ($chunk['imports'] as $importedKey) {
+                foreach ($this->collectCss($manifest, $importedKey, $visited) as $cssFile) {
+                    $css[$cssFile] = true;
+                }
+            }
+        }
+
+        return array_keys($css);
+    }
+
     /**
      * Check debug mode
      */
diff --git a/tests/ViteTest.php b/tests/ViteTest.php
new file mode 100644
index 0000000..9daefce
--- /dev/null
+++ b/tests/ViteTest.php
@@ -0,0 +1,239 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests;
+
+use PHPUnit\Framework\TestCase;
+use ReflectionClass;
+use ReflectionMethod;
+use ReflectionProperty;
+use Webrium\App;
+use Webrium\Url;
+use Webrium\Vite;
+
+/**
+ * Unit Tests for Webrium\Vite
+ *
+ * Coverage:
+ *  - collectCss(): direct css, transitive css via imports, dedup across
+ *    branches, cycle safety, unknown manifest key
+ *  - assets() / renderProductionTags(): end-to-end tag generation from a
+ *    manifest.json fixture, including the case where an entry owns no
+ *    direct "css" key but pulls it in through an imported chunk (the
+ *    scenario Rollup produces when two entries import the same CSS module
+ *    and one of them collapses into a shared chunk of the other)
+ */
+class ViteTest extends TestCase
+{
+    // -------------------------------------------------------------------------
+    // Helpers
+    // -------------------------------------------------------------------------
+
+    /**
+     * A Vite instance built via reflection, bypassing the protected
+     * constructor (host/port detection, dev-server probing). Used for
+     * exercising collectCss() in isolation, without any App/Url/network
+     * dependency.
+     */
+    private function bareInstance(): Vite
+    {
+        return (new ReflectionClass(Vite::class))->newInstanceWithoutConstructor();
+    }
+
+    private function collectCss(Vite $vite, array $manifest, string $entryPoint): array
+    {
+        $method = new ReflectionMethod(Vite::class, 'collectCss');
+        $method->setAccessible(true);
+
+        $visited = [];
+        return $method->invokeArgs($vite, [$manifest, $entryPoint, &$visited]);
+    }
+
+    // =========================================================================
+    // 1. collectCss()
+    // =========================================================================
+
+    public function testCollectsDirectCss(): void
+    {
+        $manifest = [
+            'app.js' => ['file' => 'app.js', 'css' => ['app.css']],
+        ];
+
+        $this->assertSame(
+            ['app.css'],
+            $this->collectCss($this->bareInstance(), $manifest, 'app.js')
+        );
+    }
+
+    /**
+     * Reproduces the real-world bug: an entry with no direct "css" key,
+     * whose only styles come from a sibling chunk it imports.
+     */
+    public function testCollectsCssTransitivelyThroughImports(): void
+    {
+        $manifest = [
+            'admin.js' => ['file' => 'admin.js', 'imports' => ['app.js']],
+            'app.js'   => ['file' => 'app.js', 'css' => ['app.css']],
+        ];
+
+        $this->assertSame(
+            ['app.css'],
+            $this->collectCss($this->bareInstance(), $manifest, 'admin.js')
+        );
+    }
+
+    public function testDedupesCssSharedAcrossMultipleImportBranches(): void
+    {
+        $manifest = [
+            'admin.js' => ['file' => 'admin.js', 'imports' => ['vendor-a.js', 'vendor-b.js']],
+            'vendor-a.js' => ['css' => ['shared.css']],
+            'vendor-b.js' => ['css' => ['shared.css']],
+        ];
+
+        $this->assertSame(
+            ['shared.css'],
+            $this->collectCss($this->bareInstance(), $manifest, 'admin.js')
+        );
+    }
+
+    public function testCombinesOwnCssWithImportedCss(): void
+    {
+        $manifest = [
+            'admin.js' => ['file' => 'admin.js', 'css' => ['admin.css'], 'imports' => ['app.js']],
+            'app.js'   => ['css' => ['app.css']],
+        ];
+
+        $this->assertSame(
+            ['admin.css', 'app.css'],
+            $this->collectCss($this->bareInstance(), $manifest, 'admin.js')
+        );
+    }
+
+    public function testCyclicImportsDoNotCauseInfiniteRecursion(): void
+    {
+        $manifest = [
+            'a.js' => ['css' => ['a.css'], 'imports' => ['b.js']],
+            'b.js' => ['css' => ['b.css'], 'imports' => ['a.js']],
+        ];
+
+        $this->assertSame(
+            ['a.css', 'b.css'],
+            $this->collectCss($this->bareInstance(), $manifest, 'a.js')
+        );
+    }
+
+    public function testUnknownManifestKeyReturnsEmptyArray(): void
+    {
+        $manifest = ['app.js' => ['css' => ['app.css']]];
+
+        $this->assertSame(
+            [],
+            $this->collectCss($this->bareInstance(), $manifest, 'missing.js')
+        );
+    }
+
+    public function testEntryWithNeitherCssNorImportsReturnsEmptyArray(): void
+    {
+        $manifest = ['app.js' => ['file' => 'app.js']];
+
+        $this->assertSame(
+            [],
+            $this->collectCss($this->bareInstance(), $manifest, 'app.js')
+        );
+    }
+
+    // =========================================================================
+    // 2. assets() / renderProductionTags() end-to-end
+    // =========================================================================
+
+    /**
+     * @runInSeparateProcess
+     * @preserveGlobalState disabled
+     */
+    public function testAssetsIncludesTransitiveCssForImportOnlyEntry(): void
+    {
+        $vite = $this->bootProductionVite([
+            'resources/js/admin.js' => [
+                'file' => 'assets/admin-hash.js',
+                'name' => 'admin',
+                'src' => 'resources/js/admin.js',
+                'isEntry' => true,
+                'imports' => ['resources/js/app.js'],
+            ],
+            'resources/js/app.js' => [
+                'file' => 'assets/app-hash.js',
+                'name' => 'app',
+                'src' => 'resources/js/app.js',
+                'isEntry' => true,
+                'css' => ['assets/app-hash.css'],
+            ],
+        ]);
+
+        $html = $vite->assets('resources/js/admin.js');
+
+        $this->assertStringContainsString(
+            '<link rel="stylesheet" href="/build/assets/app-hash.css">',
+            $html
+        );
+        $this->assertStringContainsString(
+            '<script type="module" src="/build/assets/admin-hash.js"></script>',
+            $html
+        );
+    }
+
+    /**
+     * @runInSeparateProcess
+     * @preserveGlobalState disabled
+     */
+    public function testAssetsStillWorksForEntryWithOwnDirectCss(): void
+    {
+        $vite = $this->bootProductionVite([
+            'resources/js/app.js' => [
+                'file' => 'assets/app-hash.js',
+                'isEntry' => true,
+                'css' => ['assets/app-hash.css'],
+            ],
+        ]);
+
+        $html = $vite->assets('resources/js/app.js');
+
+        $this->assertStringContainsString(
+            '<link rel="stylesheet" href="/build/assets/app-hash.css">',
+            $html
+        );
+        $this->assertStringContainsString(
+            '<script type="module" src="/build/assets/app-hash.js"></script>',
+            $html
+        );
+    }
+
+    /**
+     * Boots a fresh Vite singleton against a temp project root containing
+     * the given manifest, forced into production mode (isDev = false) so
+     * the test is deterministic regardless of whether a real Vite dev
+     * server happens to be listening on the default port.
+     */
+    private function bootProductionVite(array $manifest): Vite
+    {
+        $root = sys_get_temp_dir() . '/webrium_vite_test_' . uniqid();
+        mkdir($root . '/public/build/.vite', 0755, true);
+        file_put_contents(
+            $root . '/public/build/.vite/manifest.json',
+            json_encode($manifest)
+        );
+
+        App::setRootPath($root);
+        $_SERVER['DOCUMENT_ROOT'] = $root;
+        Url::reset();
+
+        $vite = Vite::getInstance();
+        $vite->setBasePath($root);
+
+        $isDev = new ReflectionProperty(Vite::class, 'isDev');
+        $isDev->setAccessible(true);
+        $isDev->setValue($vite, false);
+
+        return $vite;
+    }
+}