What does this PR do? What is the motivation?

Two UI fixes reported on the docs site:

1. ToC incorrect highlight (Catalog page): The site-region shortcode renders region-gated headings inside a display:none container. Because getBoundingClientRect() returns all zeros for hidden elements, the scroll-spy treated those headings as always at the top of the page. This caused the hidden heading's parent to appear highlighted in the ToC regardless of scroll position. Fix: getHeaderTop() helper returns localOffset + 1 for zero-sized elements so hidden headings never satisfy the scroll condition.

2. Search input text overlap with "/" shortcut indicator: The ::after keyboard shortcut hint element overlaps long query text at certain viewport widths. Fix: added padding-right: 30px to .ais-SearchBox-input on both the search results page and the navbar search to keep text clear of the indicator.

motivation: bug fix: WEB-9223

preview:

• https://docs-staging.datadoghq.com/stefon.simmons/web-9223/internal_developer_portal/catalog/
  • check that the scrolled-to header is highlighted in the TOC
• https://docs-staging.datadoghq.com/stefon.simmons/web-9223/search/?s=what%20are%20the%20command%20line%20tools%20Datadog%20provides%3F
• https://docs-staging.datadoghq.com/stefon.simmons/web-9223/infrastructure/?s=what%20are%20the%20command%20line%20tools%20Datadog%20provides%3F
  • check that keyboard shortcut hint ([ / ]) does not overlap long search input

Merge instructions

Merge readiness:

• Ready for merge

AI assistance

Claude Code assisted with root cause analysis and initial implementation.

Additional notes