[BUG] Elements modal fixes

[matKlju]

AS A Service Administrator
I WANT the Elements modal and its sections to follow a unified dark mode and visual styling standard
SO THAT the UI remains visually consistent, readable, and aligned with the overall Service Module design system

Description

The Elements modal currently contains visual inconsistencies between the "All elements" section and the "API elements" section. In dark mode, the API Elements area does not fully conform to the application's dark mode styling standards and appears visually detached from the rest of the modal.

Additionally, the embedded API mini-modal/component uses different styling patterns, spacing, colors, and borders compared to the surrounding modal UI, creating an inconsistent user experience.

This task focuses on aligning the full Elements modal styling and structure into a single coherent visual standard.

Acceptance Criteria

• API Elements section fully supports dark mode styling
• Backgrounds, borders, hover states, text colors, and inputs match dark mode standards
• General Elements and API Elements sections use a unified visual design language
• API mini-modal/component styling is aligned with the overall Elements modal styling
• Consistent spacing, padding, typography, border radius, and shadows are applied across sections
• No visually detached or differently themed components remain inside the modal
• Styling remains responsive and readable on different screen sizes
• Existing functionality remains unchanged

Notes

• Focus is visual/UI consistency only
• No backend or logic changes included

##Screenshots

[matKlju]

AT-passed