Table modal uses light background causing low contrast in dark mode

### Description

When viewing documentation tables in dark mode and expanding a table (fullscreen/modal view), the modal container background switches to white while the text color remains light/white. As a result, the text has insufficient contrast and becomes unreadable.

Affected URL: [https://goharbor.io/docs/2.9.0/install-config/configure-yml-file/](https://goharbor.io/docs/2.9.0/install-config/configure-yml-file/)

### Steps to Reproduce

1. Go to Harbor docs with dark mode enabled (or system dark mode active).
2. Navigate to a page containing a table (e.g., `configure-yml-file`).
3. Click to enlarge/expand the table modal.
4. Observe the modal theme styling.

### Expected Behavior

The expanded table modal should inherit dark mode styling (dark background with readable light text) or use appropriately contrasted text colors.

### Actual Behavior

The expanded modal background renders as white, causing light-colored text to blend into the background and become unreadable.

### Screenshots

Start at the affected configure-yml-file documentation page and trace the expanded table modal and its dark-mode styling. Reproduce the issue with dark mode enabled, then verify that the modal background and text provide readable contrast when the table is expanded.

Written by the indexing model from the issue text.