Home and Admin had no horizontal padding below the sm breakpoint (640px),
causing content to bleed to viewport edges. Admin's flex justify-between
row with h1 + 4 tab buttons overflowed by ~110px at 320px.
- +page.svelte: add px-4 to <main> (sm:px-6 lg:px-8 unchanged)
- admin/+page.svelte: add px-4 to outer container; stack header row
vertically on mobile (flex-col sm:flex-row); reduce tab button padding
to px-2 on mobile (sm:px-4 on desktop)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>