Edited css not updated in XAMPP

Joomla's default Protostar template includes CSS files with

JHtml::_('stylesheet', 'template.css', array('version' => 'auto', 'relative' => true));

The ['version' => 'auto'] adds a media version MD5 hash as token to the file. The media version is regenerated by Joomla whenever anything is installed on the Joomla instance. See https://docs.joomla.org/J3.x:Adding_JavaScript_and_CSS_to_the_page#.24options_and_.24attributes_Parameters

The media version does NOT change when you make changes in your CSS. You could add your own timestamp to force a browser to re-load the CSS instead using it from cache.

In your template's index.php you could add something like:

use JoomlaCMSHTMLHTMLHelper;

HTMLHelper::_(
    'stylesheet',
    'your-css-file.css',
    [
        'version'  => filemtime(JPATH_THEMES
            . '/your-template/css/your-css-file.css'),
        'relative' => true
    ]
);