[Feedback]: Poor visual contrast makes API docs difficult to read

### Was the documentation helpful?

Yes

### What documentation page is affected

https://www.elastic.co/docs/api/doc/kibana/v8

### Description

I find the API doc pages difficult to read. The visual elements feel too 'soft'; there's not enough contrast or clear separation between sections. This causes everything to sort of blend together, making it hard to quickly identify headings and content. Stronger visual cues would improve readability.

|Current|Proposed|
|---|---|
|||