How to deactivate linked styles
When editing your page in the WYSIWYG drag and drop editor, you may see a notice that says "This element shares style with ... other elements...." as in the sample below
This means that any customization applied to one of the 4 list items as shown in the image above will automatically apply to the rest of the list items.
This is a way to help you in building and customizing your pages as fast as possible.
At at point if you prefer to de-link/separate the styling for the linked items, you can easily do that by giving each element a unique content ID.
Select the element you want to de-link/separate its style, and click on Content by the left menu tabs
Enter a unique ID for this element under General
Click on the Save button to save the changes
Now you can customize the separated element without it auto-applying to other elements.