Fix remaining code quality issues

- Fixed method names to use snake_case as required by WordPress coding standards
- Added proper spacing in filter_input function call
- Added periods at the end of inline comments
- Fixed parameter documentation in Plugin class
- Updated CSS media query to use context notation

admin/css/admin-styles.css

@@ -124,7 +124,7 @@
 }
 
 /* Responsive Styles */
-@media screen and (max-width: 782px) {
+@media screen and (width <= 782px) {
 	.wpst-form-table th {
 		width: 100%;
 		display: block;