Swap to shadcn components and polish the design

Components (added via the shadcn MCP/CLI):
- Navbar: NavigationMenu on desktop, Sheet on mobile; drops
  Navbar.module.css and the hand-rolled slide-down menu
- Buttons: shadcn Button via a shared ContactButtons component
  (replaces Button.js and its CSS module)
- Card for price cards, testimonials, the business block and plan;
  Table for prices; Input/Textarea/Label/NativeSelect/RadioGroup and
  Alert in the quote form; Separator in the footer
- Components import cn from @/lib/utils (not the new "cn" package);
  accordion moved to the unified radix-ui package

Design tweaks:
- Geist Sans is actually applied (font variables were on <body>, but
  Tailwind reads them on <html>, so the site fell back to system fonts)
- Theme primary set to the existing brand blue; slightly smaller radius
- Balanced, tighter heading tracking; muted secondary text
- 44px contact buttons; 16px FAQ text; tighter homepage spacing
- Full-width selects with 16px text on phones (no iOS zoom)

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/components/ui/alert.jsx

@@ -0,0 +1,68 @@
+import * as React from "react"
+import { cva } from "class-variance-authority";
+import { cn } from "@/lib/utils"
+
+const alertVariants = cva(
+  "relative grid w-full grid-cols-[0_1fr] items-start gap-y-0.5 rounded-lg border px-4 py-3 text-sm has-[>svg]:grid-cols-[calc(var(--spacing)*4)_1fr] has-[>svg]:gap-x-3 [&>svg]:size-4 [&>svg]:translate-y-0.5 [&>svg]:text-current",
+  {
+    variants: {
+      variant: {
+        default: "bg-card text-card-foreground",
+        destructive:
+          "bg-card text-destructive *:data-[slot=alert-description]:text-destructive/90 [&>svg]:text-current",
+      },
+    },
+    defaultVariants: {
+      variant: "default",
+    },
+  }
+)
+
+function Alert({
+  className,
+  variant,
+  ...props
+}) {
+  return (
+    <div
+      data-slot="alert"
+      role="alert"
+      className={cn(alertVariants({ variant }), className)}
+      {...props}
+    />
+  )
+}
+
+function AlertTitle({
+  className,
+  ...props
+}) {
+  return (
+    <div
+      data-slot="alert-title"
+      className={cn(
+        "col-start-2 line-clamp-1 min-h-4 font-medium tracking-tight",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function AlertDescription({
+  className,
+  ...props
+}) {
+  return (
+    <div
+      data-slot="alert-description"
+      className={cn(
+        "col-start-2 grid justify-items-start gap-1 text-sm text-muted-foreground [&_p]:leading-relaxed",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+export { Alert, AlertTitle, AlertDescription }