typo3/sysext/core/Classes/Page/PageRenderer.php    | 28 +++++++++++++++-------
 .../sysext/frontend/Classes/Page/PageGenerator.php |  3 ++-
 2 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/typo3/sysext/core/Classes/Page/PageRenderer.php b/typo3/sysext/core/Classes/Page/PageRenderer.php
index a2ffbbf..5ff4343 100644
--- a/typo3/sysext/core/Classes/Page/PageRenderer.php
+++ b/typo3/sysext/core/Classes/Page/PageRenderer.php
@@ -1354,8 +1354,9 @@ class PageRenderer implements \TYPO3\CMS\Core\SingletonInterface
      * @param string $allWrap
      * @param bool $excludeFromConcatenation
      * @param string $splitChar The char used to split the allWrap value, default is "|"
+     * @param bool $forceInline
      */
-    public function addCssFile($file, $rel = 'stylesheet', $media = 'all', $title = '', $compress = true, $forceOnTop = false, $allWrap = '', $excludeFromConcatenation = false, $splitChar = '|')
+    public function addCssFile($file, $rel = 'stylesheet', $media = 'all', $title = '', $compress = true, $forceOnTop = false, $allWrap = '', $excludeFromConcatenation = false, $splitChar = '|', $forceInline = false)
     {
         if (!isset($this->cssFiles[$file])) {
             $this->cssFiles[$file] = [
@@ -1367,7 +1368,8 @@ class PageRenderer implements \TYPO3\CMS\Core\SingletonInterface
                 'forceOnTop' => $forceOnTop,
                 'allWrap' => $allWrap,
                 'excludeFromConcatenation' => $excludeFromConcatenation,
-                'splitChar' => $splitChar
+                'splitChar' => $splitChar,
+                'forceInline' => $forceInline
             ];
         }
     }
@@ -2208,12 +2210,22 @@ class PageRenderer implements \TYPO3\CMS\Core\SingletonInterface
         $cssFiles = '';
         if (!empty($this->cssFiles)) {
             foreach ($this->cssFiles as $file => $properties) {
-                $file = $this->getStreamlinedFileName($file);
-                $tag = '<link rel="' . htmlspecialchars($properties['rel'])
-                    . '" type="text/css" href="' . htmlspecialchars($file)
-                    . '" media="' . htmlspecialchars($properties['media']) . '"'
-                    . ($properties['title'] ? ' title="' . htmlspecialchars($properties['title']) . '"' : '')
-                    . $this->endingSlash . '>';
+                $href = $this->getStreamlinedFileName($file);
+                if ($properties['forceInline'] && @is_file($file)) {
+                    $cssInline = file_get_contents($file);
+                    $tag = '<style type="text/css"'
+                        . ' media="' . htmlspecialchars($properties['media']) . '"'
+                        . ($properties['title'] ? ' title="' . htmlspecialchars($properties['title']) . '"' : '')
+                        . '>' . "\n"
+                        . $cssInline
+                        . '</style>';
+                } else {
+                    $tag = '<link rel="' . htmlspecialchars($properties['rel'])
+                        . '" type="text/css" href="' . htmlspecialchars($href)
+                        . '" media="' . htmlspecialchars($properties['media']) . '"'
+                        . ($properties['title'] ? ' title="' . htmlspecialchars($properties['title']) . '"' : '')
+                        . $this->endingSlash . '>';
+                }
                 if ($properties['allWrap']) {
                     $wrapArr = explode($properties['splitChar'] ?: '|', $properties['allWrap'], 2);
                     $tag = $wrapArr[0] . $tag . $wrapArr[1];
diff --git a/typo3/sysext/frontend/Classes/Page/PageGenerator.php b/typo3/sysext/frontend/Classes/Page/PageGenerator.php
index 5ca0187..ef1034f 100644
--- a/typo3/sysext/frontend/Classes/Page/PageGenerator.php
+++ b/typo3/sysext/frontend/Classes/Page/PageGenerator.php
@@ -304,7 +304,8 @@ class PageGenerator
                                 (bool)$cssFileConfig['forceOnTop'],
                                 $cssFileConfig['allWrap'],
                                 (bool)$cssFileConfig['excludeFromConcatenation'],
-                                $cssFileConfig['allWrap.']['splitChar']
+                                $cssFileConfig['allWrap.']['splitChar'],
+                                $cssFileConfig['forceInline']
                             );
                             unset($cssFileConfig);
                         }