[jrodal98]

The viewport meta added in #59 exposed that the CSS had no responsive rules at all (zero @media queries): at phone width the nav wrapped into a staggered mess, the manage tab bar overflowed off-screen, and wide tables pushed the whole page sideways.

Measured at a 393px viewport (Playwright, logged-in admin), page width before -> after:

• /manage (Create tab): 544px -> 393px
• /manage (My Bookmarks): 919px -> 393px
• /settings: 429px -> 393px (API token table)
• /admin: 499px -> 393px (user table)
• /help and /: already fit, unchanged
  Desktop (1280px) verified unchanged.

Changes:

• main.css: .table-scroll wrapper (tables keep a 720px min width and scroll horizontally inside it instead of squeezing); @media (max-width: 768px) stacks the nav into centered wrapping rows, tightens container/cell padding, and lets long inline code samples wrap.
• manage.css: tab bar scrolls horizontally on small screens instead of overflowing.
• Templates: tables wrapped in .table-scroll (manage x2, admin, help x2, API token list, nested list; the nested table also drops its inline width style). The HTMX OOB-swapped personal-bookmarks table is wrapped at its include site, so swaps are unaffected.
• tests/responsive_test.rs: guards the media queries, the .table-scroll CSS, and the wrappers on /manage, /help, /admin.

Verified: full cargo test suite green, plus Playwright screenshots at 393x852 (all pages fit, nav/tabs/tables clean) and 1280px desktop (no regression). Screenshots were taken against a locally seeded server; seed data included deliberately long URLs/descriptions to stress wrapping.