I installed CiviCRM V5.7 with shoreditch theme on localhost computer and looks good. I am accessing a site from another computer but not looking good (UI).As per the shoreditch extension, I put 'seven' as default theme.
Your screenshot shows the URL for CSS files at "http://localhost". This suggests that either your
civicrm.settings.php is incorrectly set to
localhost, or that the same problem exists in one of the directories or Resource URLs (in Administer menu » System Settings » Directories or Resource URLs).