diff --git a/Formatter/OutputFormatter.php b/Formatter/OutputFormatter.php
index 600cf76f5..4e4d3dfd3 100644
--- a/Formatter/OutputFormatter.php
+++ b/Formatter/OutputFormatter.php
@@ -166,7 +166,7 @@ public function formatAndWrap(string $message, int $width)
             if (!$open && !$tag) {
                 // </>
                 $this->styleStack->pop();
-            } elseif (false === $style = $this->createStyleFromString(strtolower($tag))) {
+            } elseif (false === $style = $this->createStyleFromString($tag)) {
                 $output .= $this->applyCurrentStyle($text, $output, $width, $currentLineLength);
             } elseif ($open) {
                 $this->styleStack->push($style);
@@ -210,15 +210,16 @@ private function createStyleFromString(string $string)
         $style = new OutputFormatterStyle();
         foreach ($matches as $match) {
             array_shift($match);
+            $match[0] = strtolower($match[0]);
 
             if ('fg' == $match[0]) {
-                $style->setForeground($match[1]);
+                $style->setForeground(strtolower($match[1]));
             } elseif ('bg' == $match[0]) {
-                $style->setBackground($match[1]);
+                $style->setBackground(strtolower($match[1]));
             } elseif ('href' === $match[0]) {
                 $style->setHref($match[1]);
             } elseif ('options' === $match[0]) {
-                preg_match_all('([^,;]+)', $match[1], $options);
+                preg_match_all('([^,;]+)', strtolower($match[1]), $options);
                 $options = array_shift($options);
                 foreach ($options as $option) {
                     $style->setOption($option);