Bug fixes / support for WP5.8 widget block editor

【Contents of the fix】
■Support for the WordPress 5.8 widget block editor
■Fixed a bug where the category name and title would be covered when the eye catching image in a blog post was set to be hidden.
■Fixed an error that occurs on the archive page of custom post type “Ranking”.

【Modified files】
css/design-plus.css
css/responsive.css
functions/category.php
archive-ranking.php
functions.php
style.css