Redesign root-domain landing page (avalanche centers list)

[busbyk]

This was generated by AI during triage.

The root domain (avy-fx.org) currently serves a hardcoded React landing page that lists the avalanche centers as logos/links (the frontend root route, distinct from the [center] tenant routes). It's functional but visually plain, and it's the first thing anyone sees at the platform's root. This issue is a visual refresh of that page.

It's tightly coupled to two neighbors at the root domain, hence the labels:

• Blocked by AvyFx branding -> Avy #647 (AvyFx → Avy rename). The rename touches the brand logo/name components this page renders. Do the rename first (or in the same PR) to avoid redoing the header/branding twice.
• Coordinate with User can learn about Avy-Fx + team #242 (platform About page). User can learn about Avy-Fx + team #242 adds a static About page as a sibling to this landing page and requires the two to "read as one site." Ideally the same agent does both in one PR so the visual language is shared; at minimum they must end up consistent.

Agent Brief

Category: enhancement
Summary: Redesign the root-domain landing page (the avalanche-centers list) to look more polished and intentional, consistent with the new About page and the post-rename branding.

Current behavior:
The frontend root-domain route renders a hardcoded React page listing avalanche centers (logos + links), sourced from the central avalanche-centers definition (the module that holds each center's slug and custom domain). Layout and styling are minimal.

Desired behavior:
A visually refined landing page that presents the platform and routes visitors to each avalanche center. Concrete, verifiable goals (aesthetic direction is intentionally open — the maintainer may add specifics or review the result):

• Uses the project's existing design system (Tailwind + the shared UI primitives), not bespoke one-off CSS.
• Clear visual hierarchy: platform identity/branding at top, then the centers as an organized, scannable grid or list.
• Fully responsive (mobile → desktop) with no layout breakage.
• Accessible: proper heading order, alt text on center logos, keyboard-navigable links, sufficient contrast in both light and dark.
• Visually consistent with the new platform About page (User can learn about Avy-Fx + team #242) — shared header/branding, spacing, and typography.

Key interfaces:

• The frontend root-domain route (the hardcoded landing page that lists centers — the root route, NOT the [center]/[slug] tenant route).
• The central avalanche-centers source of truth for the list of centers and their domains — keep consuming it; don't hardcode a duplicate list.
• Shared brand components (logo/site-name) — consume whatever AvyFx branding -> Avy #647 lands so this page follows the rename automatically.

Acceptance criteria:

• The root-domain landing page is visibly refreshed and uses the shared design system.
• The centers list is driven by the existing central definition (no duplicated hardcoded list).
• Responsive with no breakage from mobile to desktop; passes a basic accessibility check (headings, alt text, contrast, keyboard nav).
• Branding matches the post-AvyFx branding -> Avy #647 "Avy" naming (no lingering "Avy-Fx" strings introduced here).
• Visually consistent with the User can learn about Avy-Fx + team #242 About page.

Out of scope:

• Making the landing page CMS-editable — that's the root-domain website builder (Website Builder for Root Domain (i.e. avy-fx.org) #1052).
• Changing tenant (per-center) homepages or any [center] route.
• The rename itself (AvyFx branding -> Avy #647) and the About page content (User can learn about Avy-Fx + team #242) — coordinate with, don't absorb.

[busbyk]

This was generated by AI during triage.

Folded in from #598 (closed as subsumed): light/transparent-background center icons (e.g. Sierra's) wash out on this landing page against the current color scheme, even though they look fine on the live site against each center's color palette. As part of the redesign, give each center icon a background matching its live-site header color (plus a little padding) so the centers read consistently and legibly here.

Also noted in that thread (context, not scope for this issue): this page may eventually become avalanche.org and gain a national danger map. Out of scope for the redesign, but worth knowing so the layout doesn't preclude it.