Reply To: Issue with default theme page title

you seem to have a custom.css and around line 3009 you have
#seacrh-result-title .container {
padding: 20px 0;
}

amend this to

#seacrh-result-title .container {
padding: 20px 0;
border-bottom: 1px solid #ecf0f1;
}

That should work !