diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index 6390e0fc21..4b12f171e1 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -3940,31 +3940,6 @@ parameters:
 			count: 1
 			path: src/PhpSpreadsheet/Reader/Xlsx.php
 
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Reader\\\\Xlsx\\:\\:readColor\\(\\) has no return typehint specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Reader/Xlsx.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Reader\\\\Xlsx\\:\\:readColor\\(\\) has parameter \\$background with no typehint specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Reader/Xlsx.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Reader\\\\Xlsx\\:\\:readColor\\(\\) has parameter \\$color with no typehint specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Reader/Xlsx.php
-
-		-
-			message: "#^Parameter \\#1 \\$hex of static method PhpOffice\\\\PhpSpreadsheet\\\\Style\\\\Color\\:\\:changeBrightness\\(\\) expects string, string\\|null given\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Reader/Xlsx.php
-
-		-
-			message: "#^Parameter \\#1 \\$pValue of method PhpOffice\\\\PhpSpreadsheet\\\\Style\\\\Font\\:\\:setSize\\(\\) expects float, string given\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Reader/Xlsx.php
-
 		-
 			message: "#^Cannot access property \\$r on SimpleXMLElement\\|null\\.$#"
 			count: 2
diff --git a/src/PhpSpreadsheet/Reader/Xlsx.php b/src/PhpSpreadsheet/Reader/Xlsx.php
index a7c71c7373..52a6c23832 100644
--- a/src/PhpSpreadsheet/Reader/Xlsx.php
+++ b/src/PhpSpreadsheet/Reader/Xlsx.php
@@ -27,12 +27,8 @@
 use PhpOffice\PhpSpreadsheet\Shared\Font;
 use PhpOffice\PhpSpreadsheet\Shared\StringHelper;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
-use PhpOffice\PhpSpreadsheet\Style\Border;
-use PhpOffice\PhpSpreadsheet\Style\Borders;
 use PhpOffice\PhpSpreadsheet\Style\Color;
-use PhpOffice\PhpSpreadsheet\Style\Fill;
 use PhpOffice\PhpSpreadsheet\Style\NumberFormat;
-use PhpOffice\PhpSpreadsheet\Style\Protection;
 use PhpOffice\PhpSpreadsheet\Style\Style;
 use PhpOffice\PhpSpreadsheet\Worksheet\HeaderFooterDrawing;
 use PhpOffice\PhpSpreadsheet\Worksheet\Worksheet;
@@ -1570,31 +1566,6 @@ public function load($pFilename)
         return $excel;
     }
 
-    private static function readColor($color, $background = false)
-    {
-        if (isset($color['rgb'])) {
-            return (string) $color['rgb'];
-        } elseif (isset($color['indexed'])) {
-            return Color::indexedColor($color['indexed'] - 7, $background)->getARGB();
-        } elseif (isset($color['theme'])) {
-            if (self::$theme !== null) {
-                $returnColour = self::$theme->getColourByIndex((int) $color['theme']);
-                if (isset($color['tint'])) {
-                    $tintAdjust = (float) $color['tint'];
-                    $returnColour = Color::changeBrightness($returnColour, $tintAdjust);
-                }
-
-                return 'FF' . $returnColour;
-            }
-        }
-
-        if ($background) {
-            return 'FFFFFFFF';
-        }
-
-        return 'FF000000';
-    }
-
     /**
      * @param SimpleXMLElement|stdClass $style
      */
@@ -1604,116 +1575,28 @@ private static function readStyle(Style $docStyle, $style): void
 
         // font
         if (isset($style->font)) {
-            $docStyle->getFont()->setName((string) $style->font->name['val']);
-            $docStyle->getFont()->setSize((string) $style->font->sz['val']);
-            if (isset($style->font->b)) {
-                $docStyle->getFont()->setBold(!isset($style->font->b['val']) || self::boolean((string) $style->font->b['val']));
-            }
-            if (isset($style->font->i)) {
-                $docStyle->getFont()->setItalic(!isset($style->font->i['val']) || self::boolean((string) $style->font->i['val']));
-            }
-            if (isset($style->font->strike)) {
-                $docStyle->getFont()->setStrikethrough(!isset($style->font->strike['val']) || self::boolean((string) $style->font->strike['val']));
-            }
-            $docStyle->getFont()->getColor()->setARGB(self::readColor($style->font->color));
-
-            if (isset($style->font->u) && !isset($style->font->u['val'])) {
-                $docStyle->getFont()->setUnderline(\PhpOffice\PhpSpreadsheet\Style\Font::UNDERLINE_SINGLE);
-            } elseif (isset($style->font->u, $style->font->u['val'])) {
-                $docStyle->getFont()->setUnderline((string) $style->font->u['val']);
-            }
-
-            if (isset($style->font->vertAlign, $style->font->vertAlign['val'])) {
-                $vertAlign = strtolower((string) $style->font->vertAlign['val']);
-                if ($vertAlign == 'superscript') {
-                    $docStyle->getFont()->setSuperscript(true);
-                }
-                if ($vertAlign == 'subscript') {
-                    $docStyle->getFont()->setSubscript(true);
-                }
-            }
+            Styles::readFontStyle($docStyle->getFont(), $style->font);
         }
 
         // fill
         if (isset($style->fill)) {
-            if ($style->fill->gradientFill) {
-                /** @var SimpleXMLElement $gradientFill */
-                $gradientFill = $style->fill->gradientFill[0];
-                if (!empty($gradientFill['type'])) {
-                    $docStyle->getFill()->setFillType((string) $gradientFill['type']);
-                }
-                $docStyle->getFill()->setRotation((float) ($gradientFill['degree']));
-                $gradientFill->registerXPathNamespace('sml', 'http://schemas.openxmlformats.org/spreadsheetml/2006/main');
-                $docStyle->getFill()->getStartColor()->setARGB(self::readColor(self::getArrayItem($gradientFill->xpath('sml:stop[@position=0]'))->color));
-                $docStyle->getFill()->getEndColor()->setARGB(self::readColor(self::getArrayItem($gradientFill->xpath('sml:stop[@position=1]'))->color));
-            } elseif ($style->fill->patternFill) {
-                $patternType = (string) $style->fill->patternFill['patternType'] != '' ? (string) $style->fill->patternFill['patternType'] : Fill::FILL_NONE;
-                $docStyle->getFill()->setFillType($patternType);
-                if ($style->fill->patternFill->fgColor) {
-                    $docStyle->getFill()->getStartColor()->setARGB(self::readColor($style->fill->patternFill->fgColor, true));
-                }
-                if ($style->fill->patternFill->bgColor) {
-                    $docStyle->getFill()->getEndColor()->setARGB(self::readColor($style->fill->patternFill->bgColor, true));
-                }
-            }
+            Styles::readFillStyle($docStyle->getFill(), $style->fill);
         }
 
         // border
         if (isset($style->border)) {
-            $diagonalUp = self::boolean((string) $style->border['diagonalUp']);
-            $diagonalDown = self::boolean((string) $style->border['diagonalDown']);
-            if (!$diagonalUp && !$diagonalDown) {
-                $docStyle->getBorders()->setDiagonalDirection(Borders::DIAGONAL_NONE);
-            } elseif ($diagonalUp && !$diagonalDown) {
-                $docStyle->getBorders()->setDiagonalDirection(Borders::DIAGONAL_UP);
-            } elseif (!$diagonalUp && $diagonalDown) {
-                $docStyle->getBorders()->setDiagonalDirection(Borders::DIAGONAL_DOWN);
-            } else {
-                $docStyle->getBorders()->setDiagonalDirection(Borders::DIAGONAL_BOTH);
-            }
-            self::readBorder($docStyle->getBorders()->getLeft(), $style->border->left);
-            self::readBorder($docStyle->getBorders()->getRight(), $style->border->right);
-            self::readBorder($docStyle->getBorders()->getTop(), $style->border->top);
-            self::readBorder($docStyle->getBorders()->getBottom(), $style->border->bottom);
-            self::readBorder($docStyle->getBorders()->getDiagonal(), $style->border->diagonal);
+            Styles::readBorderStyle($docStyle->getBorders(), $style->border);
         }
 
         // alignment
         if (isset($style->alignment)) {
-            $docStyle->getAlignment()->setHorizontal((string) $style->alignment['horizontal']);
-            $docStyle->getAlignment()->setVertical((string) $style->alignment['vertical']);
-
-            $textRotation = 0;
-            if ((int) $style->alignment['textRotation'] <= 90) {
-                $textRotation = (int) $style->alignment['textRotation'];
-            } elseif ((int) $style->alignment['textRotation'] > 90) {
-                $textRotation = 90 - (int) $style->alignment['textRotation'];
-            }
-
-            $docStyle->getAlignment()->setTextRotation((int) $textRotation);
-            $docStyle->getAlignment()->setWrapText(self::boolean((string) $style->alignment['wrapText']));
-            $docStyle->getAlignment()->setShrinkToFit(self::boolean((string) $style->alignment['shrinkToFit']));
-            $docStyle->getAlignment()->setIndent((int) ((string) $style->alignment['indent']) > 0 ? (int) ((string) $style->alignment['indent']) : 0);
-            $docStyle->getAlignment()->setReadOrder((int) ((string) $style->alignment['readingOrder']) > 0 ? (int) ((string) $style->alignment['readingOrder']) : 0);
+            Styles::readAlignmentStyle($docStyle->getAlignment(), $style->alignment);
         }
 
         // protection
         if (isset($style->protection)) {
-            if (isset($style->protection['locked'])) {
-                if (self::boolean((string) $style->protection['locked'])) {
-                    $docStyle->getProtection()->setLocked(Protection::PROTECTION_PROTECTED);
-                } else {
-                    $docStyle->getProtection()->setLocked(Protection::PROTECTION_UNPROTECTED);
-                }
-            }
-
-            if (isset($style->protection['hidden'])) {
-                if (self::boolean((string) $style->protection['hidden'])) {
-                    $docStyle->getProtection()->setHidden(Protection::PROTECTION_PROTECTED);
-                } else {
-                    $docStyle->getProtection()->setHidden(Protection::PROTECTION_UNPROTECTED);
-                }
-            }
+            Styles::readProtectionLocked($docStyle, $style->protection);
+            Styles::readProtectionHidden($docStyle, $style->protection);
         }
 
         // top-level style settings
@@ -1722,19 +1605,6 @@ private static function readStyle(Style $docStyle, $style): void
         }
     }
 
-    /**
-     * @param SimpleXMLElement $eleBorder
-     */
-    private static function readBorder(Border $docBorder, $eleBorder): void
-    {
-        if (isset($eleBorder['style'])) {
-            $docBorder->setBorderStyle((string) $eleBorder['style']);
-        }
-        if (isset($eleBorder->color)) {
-            $docBorder->getColor()->setARGB(self::readColor($eleBorder->color));
-        }
-    }
-
     /**
      * @param SimpleXMLElement | null $is
      *
@@ -1763,7 +1633,7 @@ private function parseRichText(?SimpleXMLElement $is)
                             $objText->getFont()->setSize((float) $run->rPr->sz['val']);
                         }
                         if (isset($run->rPr->color)) {
-                            $objText->getFont()->setColor(new Color(self::readColor($run->rPr->color)));
+                            $objText->getFont()->setColor(new Color(Styles::readColor($run->rPr->color)));
                         }
                         if (
                             (isset($run->rPr->b['val']) && self::boolean((string) $run->rPr->b['val'])) ||
@@ -1949,11 +1819,17 @@ private function readProtection(Spreadsheet $excel, SimpleXMLElement $xmlWorkboo
         }
 
         if ($xmlWorkbook->workbookProtection['revisionsPassword']) {
-            $excel->getSecurity()->setRevisionsPassword((string) $xmlWorkbook->workbookProtection['revisionsPassword'], true);
+            $excel->getSecurity()->setRevisionsPassword(
+                (string) $xmlWorkbook->workbookProtection['revisionsPassword'],
+                true
+            );
         }
 
         if ($xmlWorkbook->workbookProtection['workbookPassword']) {
-            $excel->getSecurity()->setWorkbookPassword((string) $xmlWorkbook->workbookProtection['workbookPassword'], true);
+            $excel->getSecurity()->setWorkbookPassword(
+                (string) $xmlWorkbook->workbookProtection['workbookPassword'],
+                true
+            );
         }
     }
 
diff --git a/src/PhpSpreadsheet/Reader/Xlsx/Styles.php b/src/PhpSpreadsheet/Reader/Xlsx/Styles.php
index c43ccc971f..2b0c7016f3 100644
--- a/src/PhpSpreadsheet/Reader/Xlsx/Styles.php
+++ b/src/PhpSpreadsheet/Reader/Xlsx/Styles.php
@@ -40,7 +40,7 @@ public function setStyleBaseData(?Theme $theme = null, $styles = [], $cellStyles
         $this->cellStyles = $cellStyles;
     }
 
-    private static function readFontStyle(Font $fontStyle, SimpleXMLElement $fontStyleXml): void
+    public static function readFontStyle(Font $fontStyle, SimpleXMLElement $fontStyleXml): void
     {
         $fontStyle->setName((string) $fontStyleXml->name['val']);
         $fontStyle->setSize((float) $fontStyleXml->sz['val']);
@@ -52,7 +52,9 @@ private static function readFontStyle(Font $fontStyle, SimpleXMLElement $fontSty
             $fontStyle->setItalic(!isset($fontStyleXml->i['val']) || self::boolean((string) $fontStyleXml->i['val']));
         }
         if (isset($fontStyleXml->strike)) {
-            $fontStyle->setStrikethrough(!isset($fontStyleXml->strike['val']) || self::boolean((string) $fontStyleXml->strike['val']));
+            $fontStyle->setStrikethrough(
+                !isset($fontStyleXml->strike['val']) || self::boolean((string) $fontStyleXml->strike['val'])
+            );
         }
         $fontStyle->getColor()->setARGB(self::readColor($fontStyleXml->color));
 
@@ -84,7 +86,7 @@ private static function readNumberFormat(NumberFormat $numfmtStyle, SimpleXMLEle
         }
     }
 
-    private static function readFillStyle(Fill $fillStyle, SimpleXMLElement $fillStyleXml): void
+    public static function readFillStyle(Fill $fillStyle, SimpleXMLElement $fillStyleXml): void
     {
         if ($fillStyleXml->gradientFill) {
             /** @var SimpleXMLElement $gradientFill */
@@ -94,15 +96,20 @@ private static function readFillStyle(Fill $fillStyle, SimpleXMLElement $fillSty
             }
             $fillStyle->setRotation((float) ($gradientFill['degree']));
             $gradientFill->registerXPathNamespace('sml', 'http://schemas.openxmlformats.org/spreadsheetml/2006/main');
-            $fillStyle->getStartColor()->setARGB(self::readColor(self::getArrayItem($gradientFill->xpath('sml:stop[@position=0]'))->color));
-            $fillStyle->getEndColor()->setARGB(self::readColor(self::getArrayItem($gradientFill->xpath('sml:stop[@position=1]'))->color));
+            $fillStyle->getStartColor()->setARGB(
+                self::readColor(self::getArrayItem($gradientFill->xpath('sml:stop[@position=0]'))->color)
+            );
+            $fillStyle->getEndColor()->setARGB(
+                self::readColor(self::getArrayItem($gradientFill->xpath('sml:stop[@position=1]'))->color)
+            );
         } elseif ($fillStyleXml->patternFill) {
-            $patternType = (string) $fillStyleXml->patternFill['patternType'] != '' ? (string) $fillStyleXml->patternFill['patternType'] : Fill::FILL_NONE;
+            $patternType = (string) $fillStyleXml->patternFill['patternType'] != ''
+                ? (string) $fillStyleXml->patternFill['patternType']
+                : Fill::FILL_NONE;
+
             $fillStyle->setFillType($patternType);
             if ($fillStyleXml->patternFill->fgColor) {
                 $fillStyle->getStartColor()->setARGB(self::readColor($fillStyleXml->patternFill->fgColor, true));
-            } else {
-                $fillStyle->getStartColor()->setARGB('FF000000');
             }
             if ($fillStyleXml->patternFill->bgColor) {
                 $fillStyle->getEndColor()->setARGB(self::readColor($fillStyleXml->patternFill->bgColor, true));
@@ -110,7 +117,7 @@ private static function readFillStyle(Fill $fillStyle, SimpleXMLElement $fillSty
         }
     }
 
-    private static function readBorderStyle(Borders $borderStyle, SimpleXMLElement $borderStyleXml): void
+    public static function readBorderStyle(Borders $borderStyle, SimpleXMLElement $borderStyleXml): void
     {
         $diagonalUp = self::boolean((string) $borderStyleXml['diagonalUp']);
         $diagonalDown = self::boolean((string) $borderStyleXml['diagonalDown']);
@@ -141,7 +148,7 @@ private static function readBorder(Border $border, SimpleXMLElement $borderXml):
         }
     }
 
-    private static function readAlignmentStyle(Alignment $alignment, SimpleXMLElement $alignmentXml): void
+    public static function readAlignmentStyle(Alignment $alignment, SimpleXMLElement $alignmentXml): void
     {
         $alignment->setHorizontal((string) $alignmentXml['horizontal']);
         $alignment->setVertical((string) $alignmentXml['vertical']);
@@ -156,8 +163,12 @@ private static function readAlignmentStyle(Alignment $alignment, SimpleXMLElemen
         $alignment->setTextRotation((int) $textRotation);
         $alignment->setWrapText(self::boolean((string) $alignmentXml['wrapText']));
         $alignment->setShrinkToFit(self::boolean((string) $alignmentXml['shrinkToFit']));
-        $alignment->setIndent((int) ((string) $alignmentXml['indent']) > 0 ? (int) ((string) $alignmentXml['indent']) : 0);
-        $alignment->setReadOrder((int) ((string) $alignmentXml['readingOrder']) > 0 ? (int) ((string) $alignmentXml['readingOrder']) : 0);
+        $alignment->setIndent(
+            (int) ((string) $alignmentXml['indent']) > 0 ? (int) ((string) $alignmentXml['indent']) : 0
+        );
+        $alignment->setReadOrder(
+            (int) ((string) $alignmentXml['readingOrder']) > 0 ? (int) ((string) $alignmentXml['readingOrder']) : 0
+        );
     }
 
     private function readStyle(Style $docStyle, $style): void
@@ -186,8 +197,8 @@ private function readStyle(Style $docStyle, $style): void
 
         // protection
         if (isset($style->protection)) {
-            $this->readProtectionLocked($docStyle, $style);
-            $this->readProtectionHidden($docStyle, $style);
+            self::readProtectionLocked($docStyle, $style);
+            self::readProtectionHidden($docStyle, $style);
         }
 
         // top-level style settings
@@ -196,7 +207,7 @@ private function readStyle(Style $docStyle, $style): void
         }
     }
 
-    private function readProtectionLocked(Style $docStyle, $style): void
+    public static function readProtectionLocked(Style $docStyle, $style): void
     {
         if (isset($style->protection['locked'])) {
             if (self::boolean((string) $style->protection['locked'])) {
@@ -207,7 +218,7 @@ private function readProtectionLocked(Style $docStyle, $style): void
         }
     }
 
-    private function readProtectionHidden(Style $docStyle, $style): void
+    public static function readProtectionHidden(Style $docStyle, $style): void
     {
         if (isset($style->protection['hidden'])) {
             if (self::boolean((string) $style->protection['hidden'])) {
@@ -218,7 +229,7 @@ private function readProtectionHidden(Style $docStyle, $style): void
         }
     }
 
-    private static function readColor($color, $background = false)
+    public static function readColor($color, $background = false)
     {
         if (isset($color['rgb'])) {
             return (string) $color['rgb'];