Agenda table header action buttons overlap Event column on small screens and break on mobile

[doguabaris]

Describe the issue

Description
On the IETF 125 Meeting Agenda page, the "Assign Colors to Events" and "Search Events" buttons are positioned inside the table header area in a way that breaks layout at smaller viewport widths.

Observed behavior

• On desktop, when the viewport width is reduced, both buttons overlap the "Event" column header text.
• The buttons appear visually on top of the "Event" header instead of staying aligned to the header controls area.
• On mobile view, the "Assign Colors to Events" button disappears entirely, while the "Search Events" button remains floating over the table header.

Expected behavior

• Header action buttons should not overlap column headers at any viewport size.
• Buttons should either reflow into a separate toolbar, collapse into a menu, or move above the table on small screens.
• Mobile layout should preserve access to both actions in a consistent way.

Steps to reproduce

1. Open https://datatracker.ietf.org/meeting/125/agenda
2. Resize the browser window to a narrow desktop width
3. Observe overlap on the "Event" column header
4. Switch to a mobile viewport
5. Notice that "Assign Colors to Events" is no longer visible

Screenshot

Code of Conduct

• I agree to follow the IETF's Code of Conduct