Hello,

Set the page you want to keep being active as the sub-page’s parent in Page Attribute’s (screenshot).
Let us know.

Best regards!

Hello,

Please add this code into your custom css box:

 .header_1 nav li.current-page-ancestor > a {
    color: #dd9933 !important;
}

It will give the color to the parent page, when you are in it’s child page.

Kind regards!

Hello,

Sorry but this is not possible.

Best regards!

Hello,

This is the structure of wordpress content structuring. Pages and posts are independent custom post types templates. You can sort out a parent-child dependency in pages, but it is not possible to do so with post-pages.
This is not a lack of theme rather than a rule of WordPress structure.

Best regards!