Hi @clemsonjack,
Thank you for reaching out to us. That’s the stack background color for page templates, you can override it by adding the following code in the Theme Options > CSS:
.page-template-template-blank-4-php .x-main, .page-template-template-blank-5-php .x-main, .page-template-template-blank-6-php .x-main, .page-template-template-blank-8-php .x-main {
background-color: #ccc;
}
Please note that the code provided above serves as a guide only and is to help you in getting started so implementing it and maintaining the code will be out of our support scope and for further maintenance for new possible versions of the theme that may cause the customization to break, you will need to hire a developer.
Here are some related links for further reading, this could help you in finding and implementing some CSS fixes:
Hope this helps!