Improve CSS spacing and typography hierarchy in HTML UI

Tighten up visual hierarchy and readability in the base CSS by addressing spacing and font sizing.

Spacing (.sub, .op-form label, table cells)

Current:

• .sub { margin-bottom: 1.5rem } feels cramped under h1
• .op-form label { gap: 0.15rem } is basically zero breathing room between label and input
• Table cells at padding: 0.35rem 0.5rem are punched-in

Fix: Add 20–30% more breathing room where content density makes readability hard (forms, tables, dense lists). Examples:

• .sub: increase to 2rem or 2.2rem
• .op-form label: increase gap to 0.25rem or 0.3rem
• Table cells: increase padding to 0.5rem 0.7rem or similar

Typography hierarchy (h1 vs h2, line-height, font-weight)

Current:

• h1: 1.4rem, h2: 1.1rem — only 27% size difference
• Line heights uniform at 1.5 everywhere
• No font-weight variation on headlines; h2 and body text are visually similar

Fix: Create clearer visual separation:

• Bump h2 from 1.1rem to 1.3rem or 1.4rem
• Add font-weight: 700 (or 600) to h2 (currently inherits 400)
• Consider increasing line-height on body or .op-form label to 1.6 to improve form readability
• Optionally add font-weight: 600+ to h1

Goal: A table of tickets should show h2 headlines visually distinct from surrounding text, and forms should have more vertical room for the eye to parse labels and inputs.

Applied per spec; six surgical edits inside the existing <style> block of base_with_class in src/html.rs. No new selectors, no structural changes, no color changes, no CSS added outside the named adjustments.

Specific changes (selector → before → after)

Spacing:

• .sub margin-bottom: 1.5rem → 2rem
• .op-form label gap: 0.15rem → 0.3rem
• th, td padding: 0.35rem 0.5rem → 0.5rem 0.7rem

Typography:

• body line-height: 1.5 → 1.6 (via the font shorthand 16px/1.5 → 16px/1.6)
• h1 font-weight: unset → 600
• h2 font-size: 1.1rem → 1.3rem; font-weight: unset → 700

Receipts

Commits on main, pushed to gitlab:

• 5c448c2 refactor(html): tighten CSS spacing and typography hierarchy
• bdded26 Merge branch 'feat/css-polish'

Tests (merged main):

• cargo build dev + release: clean (one expected dead_code warning on the retained replace_exact_skipping_tags, unrelated to this ticket).
• cargo test --lib: 303 passed (the prior parallel ticket 6dafb799 removed one breadcrumb test; this CSS ticket added/removed none).
• cargo test --lib html::: 41 passed (all existing html-module tests still green — none inspect CSS values).
• cargo test --test phase0: 14 passed.

Deploy: bash k8s/deploy.sh clean; pod chukwa-59bdbdf6d7-6z6fp Running 1/1.

Production verification (curling deployed HTML):

• GET https://chukwa.benac.dev/dashboard → HTTP 200. Grepped for each adjustment:
  • body { font: 16px/1.6 ... } ✓
  • h1 { font-size: 1.4rem; font-weight: 600; margin-bottom: 0.2rem; } ✓
  • h2 { font-size: 1.3rem; font-weight: 700; margin-top: 1.8rem; } ✓
  • .sub { ... margin-bottom: 2rem; } ✓
  • th, td { ... padding: 0.5rem 0.7rem; ... } ✓
  • .op-form label { ... gap: 0.3rem; ... } ✓
• GET https://chukwa.benac.dev/tickets → HTTP 200. Same CSS landmarks present (shares base_with_class).

Scope note worth flagging

The /w/:slug/... pages introduced in the web-UI viewer ticket (05b23288) use src/render.rs::wrap_document's OWN inline stylesheet, not html.rs::base_with_class. So this ticket's adjustments apply to /dashboard, /tickets, and any other page routed through base_with_class, but NOT to the world/turn/entity viewer pages. The spec scoped itself to src/html.rs:145-225 so I believe that's intentional, but if you wanted the polish to also land on the viewer pages it's a small follow-up — mirror the six edits into render.rs's stylesheet.

What was NOT changed per spec discipline

• No new selectors.
• No responsive media queries.
• No color changes.
• .links breadcrumb CSS untouched (and now dead, since the sibling _links removal shipped in the same deploy — noted in the commit body for the next reviewer to mop up if they like).
• Ticket-row pill CSS, callout, child-breakdown glyphs, all other existing rules — unchanged.

Per standing guidance I am not confirming this ticket — only proposing. Over to you.