Improve responsive behavior of search bar on mobile

[Manik-Khajuria-5]

Describe the issue

On smaller screen sizes, the full search bar in Plone Volto remains visible instead of collapsing, leading to a cluttered header layout.

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To Reproduce

1. Open a Volto site
2. Resize the browser to tablet/mobile width
3. Observe the header search area

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Expected behavior

After a defined breakpoint:

• The full search bar should be hidden
• Only a search icon should be displayed
• Clicking the icon should reveal the search input

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Current behavior

• The full search bar stays visible on small screens
• The header looks crowded and less usable

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screenrecording-2026-02-09_15-45-36.mp4