1. The problem is that you copied over the entire main stylesheet as the child theme stylesheet. style.css and functions.php are the exception to the rule, you want to do this for all files, but them as these files don’t replace the parent file, they add to it.
So, in the case for the child theme stylesheet it need only contain:
/* Theme Name: StartupPro Child Template: startuppro */ @import url("../startuppro/style.css"); START ADDITIONAL CSS BY REPLACING THIS LINE
2. Can you share a link to the exact page you’re referring to?