Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Writer/Html.php
private function createCSSStyle(Style $pStyle)
    {
        // Create CSS
        $css = array_merge(
            $this->createCSSStyleAlignment($pStyle->getAlignment()),
            $this->createCSSStyleBorders($pStyle->getBorders()),
            $this->createCSSStyleFont($pStyle->getFont()),
            $this->createCSSStyleFill($pStyle->getFill())
        );

        // Return
        return $css;
    }
private function createCSSStyle(Style $pStyle)
    {
        // Create CSS
        $css = array_merge(
            $this->createCSSStyleAlignment($pStyle->getAlignment()),
            $this->createCSSStyleBorders($pStyle->getBorders()),
            $this->createCSSStyleFont($pStyle->getFont()),
            $this->createCSSStyleFill($pStyle->getFill())
        );

        // Return
        return $css;
    }
Create CSS style.

@param Style $pStyle

@return array