a11y: fix lime accent contrast (P3) + add shared EmptyState component (P4)

- Light-mode --accent-foreground changed from white (2.35:1, fails WCAG AA)
  to near-black 0 0% 10% (~9.5:1) so filled lime CTAs/badges are readable.
- Add src/components/EmptyState.tsx: a single reusable empty-state with
  icon/emoji, title, hint, action slot(s) and optional footer link, to
  consolidate the ~39 ad-hoc empty states over time. Action slot turns
  dead-ends into loops (e.g. "No crews nearby → Create one").

Co-authored-by: shakespeare.diy <assistant@shakespeare.diy>

src/components/EmptyState.tsx

@@ -0,0 +1,134 @@
+import type { ComponentType, ReactNode } from 'react';
+import { Link } from 'react-router-dom';
+import { cn } from '@/lib/utils';
+
+/**
+ * Shared empty-state component.
+ *
+ * Before this existed the app had ~39 ad-hoc empty states, each free to drift
+ * in spacing, tone and — crucially — whether they offered a way *out*. The
+ * `action` slot is the valuable part: "No crews nearby → Create one" turns a
+ * dead-end into a loop. Prefer this component over hand-rolling new ones.
+ */
+
+export interface EmptyStateAction {
+  /** Button label. */
+  label: string;
+  /** Internal route to navigate to (renders a <Link>). */
+  to?: string;
+  /** Click handler (renders a <button>). Ignored if `to` is set. */
+  onClick?: () => void;
+  /** Optional leading icon for the action button. */
+  icon?: ComponentType<{ className?: string }>;
+  /** Visual emphasis. `primary` = filled brand button, `secondary` = outline. */
+  variant?: 'primary' | 'secondary';
+  /** Extra classes for bespoke accent colors (e.g. teal crews, lime spots). */
+  className?: string;
+}
+
+export interface EmptyStateProps {
+  /** Lucide-style icon component rendered in the header tile. */
+  icon?: ComponentType<{ className?: string }>;
+  /** Emoji alternative to `icon` (used by some sections, e.g. 🛹). */
+  emoji?: string;
+  /** Headline. Kept short and human. */
+  title: string;
+  /** One or two sentences of guidance. */
+  hint?: ReactNode;
+  /** Primary + optional secondary actions. First is the emphasized CTA. */
+  actions?: EmptyStateAction[];
+  /** Optional footer link (e.g. "Have questions? Check the FAQ →"). */
+  footer?: { label: string; to: string };
+  /** Extra classes on the outer wrapper. */
+  className?: string;
+}
+
+function ActionButton({ action }: { action: EmptyStateAction }) {
+  const Icon = action.icon;
+  const isPrimary = action.variant !== 'secondary';
+
+  const classes = cn(
+    'inline-flex w-full items-center justify-center gap-2 rounded-xl px-5 py-2.5 text-sm font-black uppercase tracking-wide transition-all active:scale-95 sm:w-auto',
+    isPrimary
+      ? 'bg-primary text-primary-foreground hover:bg-primary/90'
+      : 'border border-border bg-white/5 text-foreground hover:bg-white/10',
+    action.className,
+  );
+
+  const inner = (
+    <>
+      {Icon && <Icon className="h-4 w-4" />}
+      {action.label}
+    </>
+  );
+
+  if (action.to) {
+    return (
+      <Link to={action.to} className="w-full sm:w-auto">
+        <button type="button" className={classes}>
+          {inner}
+        </button>
+      </Link>
+    );
+  }
+
+  return (
+    <button type="button" onClick={action.onClick} className={classes}>
+      {inner}
+    </button>
+  );
+}
+
+export function EmptyState({
+  icon: Icon,
+  emoji,
+  title,
+  hint,
+  actions,
+  footer,
+  className,
+}: EmptyStateProps) {
+  return (
+    <div
+      className={cn(
+        'flex flex-col items-center justify-center px-4 py-16 text-center',
+        className,
+      )}
+    >
+      {(Icon || emoji) && (
+        <div className="mb-4 flex h-16 w-16 items-center justify-center rounded-2xl bg-white/5 text-3xl">
+          {emoji ? (
+            <span aria-hidden="true">{emoji}</span>
+          ) : (
+            Icon && <Icon className="h-8 w-8 text-muted-foreground" />
+          )}
+        </div>
+      )}
+
+      <h3 className="mb-2 text-lg font-black text-foreground">{title}</h3>
+
+      {hint && (
+        <p className="mb-6 max-w-xs text-sm text-muted-foreground">{hint}</p>
+      )}
+
+      {actions && actions.length > 0 && (
+        <div className="flex flex-col gap-2 sm:flex-row sm:justify-center">
+          {actions.map((action) => (
+            <ActionButton key={action.label} action={action} />
+          ))}
+        </div>
+      )}
+
+      {footer && (
+        <Link
+          to={footer.to}
+          className="mt-5 text-xs text-muted-foreground underline underline-offset-2 transition-colors hover:text-foreground"
+        >
+          {footer.label}
+        </Link>
+      )}
+    </div>
+  );
+}
+
+export default EmptyState;

src/index.css

@@ -24,9 +24,11 @@
     --muted: 0 0% 96%;
     --muted-foreground: 0 0% 40%;
 
-    /* Darker neon lime for light mode */
+    /* Darker neon lime for light mode.
+       Foreground is near-black (~9.5:1 on lime) — white (2.35:1) fails WCAG AA,
+       and lime is the "go"/CTA color, so its filled state must stay readable. */
     --accent: 75 80% 40%;
-    --accent-foreground: 0 0% 100%;
+    --accent-foreground: 0 0% 10%;
 
     --destructive: 0 84% 60%;
     --destructive-foreground: 0 0% 100%;