refactor: align landing page and 404 with Calculate blueprint

- Hero: remove framer-motion, CSS stagger animations, glass pill CTA button, refined typography and scroll indicator
- Stats: remove framer-motion, Lucide icons, tighter glass cards with mono labels
- ToolsGrid: remove framer-motion, editorial section heading, 4-col xl grid
- ToolCard: replace framer-motion motion.Link with plain Link + CSS hover, compact layout (icon→title→desc→badges+arrow), ElementType icon prop
- Footer: remove framer-motion, matches sidebar footer style
- BackToTop: remove framer-motion, JS scroll progress bar (1px primary line), compact glass button
- not-found: remove framer-motion and shadcn Button, glass pill CTA, 120px mono 404, CSS stagger
- page.tsx: remove unnecessary 'use client' directive

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/not-found.tsx

@@ -1,73 +1,53 @@
-'use client';
-
 import Link from 'next/link';
-import { motion } from 'framer-motion';
 import AnimatedBackground from '@/components/AnimatedBackground';
 import Logo from '@/components/Logo';
-import { Button } from '@/components/ui/button';
-import { Home } from 'lucide-react';
+import { ArrowLeft } from 'lucide-react';
 
 export default function NotFound() {
-
   return (
     <main className="relative min-h-screen dark text-foreground flex flex-col">
       <AnimatedBackground />
-      
-      <div className="flex-1 flex flex-col items-center justify-center px-4 py-20 relative z-10">
-        <div className="max-w-6xl mx-auto text-center">
-          {/* Logo */}
-          <motion.div
-            className="mb-8 flex justify-center"
-            initial={{ opacity: 0, y: -50 }}
-            animate={{ opacity: 1, y: 0 }}
-            transition={{ duration: 0.8 }}
-          >
-            <Logo size={100} />
-          </motion.div>
 
-          {/* 404 heading */}
-          <motion.h1
-            className="text-7xl md:text-9xl font-bold mb-6 text-primary"
-            initial={{ opacity: 0, y: 20 }}
-            animate={{ opacity: 1, y: 0 }}
-            transition={{ duration: 0.8, delay: 0.2 }}
-          >
+      <div className="flex-1 flex flex-col items-center justify-center px-6 py-20 relative z-10 text-center">
+
+        {/* Logo */}
+        <div style={{ animation: 'fadeIn 0.5s ease-out both' }}>
+          <Logo size={52} />
+        </div>
+
+        {/* 404 */}
+        <div
+          className="mt-8"
+          style={{ animation: 'slideUp 0.5s ease-out 0.15s both' }}
+        >
+          <span className="text-[80px] md:text-[120px] font-bold font-mono text-primary leading-none tabular-nums block">
             404
-          </motion.h1>
+          </span>
+        </div>
 
-          {/* Subtitle */}
-          <motion.p
-            className="text-xl md:text-3xl font-medium mb-4"
-            initial={{ opacity: 0, y: 20 }}
-            animate={{ opacity: 1, y: 0 }}
-            transition={{ duration: 0.8, delay: 0.4 }}
-          >
-            Page Not Found
-          </motion.p>
+        {/* Message */}
+        <div
+          className="mt-4 space-y-1"
+          style={{ animation: 'slideUp 0.5s ease-out 0.3s both' }}
+        >
+          <p className="text-sm font-medium text-foreground/70">Page not found</p>
+          <p className="text-[11px] text-muted-foreground/50 font-mono max-w-xs mx-auto leading-relaxed">
+            The tool or page you&apos;re looking for doesn&apos;t exist or has been moved.
+          </p>
+        </div>
 
-          {/* Description */}
-          <motion.p
-            className="text-base md:text-lg text-muted-foreground/80 mb-12 max-w-md mx-auto"
-            initial={{ opacity: 0, y: 20 }}
-            animate={{ opacity: 1, y: 0 }}
-            transition={{ duration: 0.8, delay: 0.6 }}
+        {/* CTA */}
+        <div
+          className="mt-8"
+          style={{ animation: 'slideUp 0.5s ease-out 0.45s both' }}
+        >
+          <Link
+            href="/"
+            className="inline-flex items-center gap-2 px-5 py-2.5 glass rounded-lg border border-primary/30 hover:border-primary/60 hover:bg-primary/10 text-sm font-medium text-foreground/70 hover:text-foreground transition-all duration-200"
           >
-            The tool or page you are looking for doesn&apos;t exist or has been moved.
-          </motion.p>
-
-          {/* CTA Button */}
-          <motion.div
-            initial={{ opacity: 0, y: 20 }}
-            animate={{ opacity: 1, y: 0 }}
-            transition={{ duration: 0.8, delay: 0.8 }}
-          >
-            <Link href="/">
-              <Button size="lg" className="rounded-full px-8 h-14 text-lg font-semibold bg-gradient-to-r from-purple-500 to-cyan-500 hover:from-purple-600 hover:to-cyan-600 border-none transition-all duration-300">
-                <Home className="mr-2 h-5 w-5" />
-                Back to Home
-              </Button>
-            </Link>
-          </motion.div>
+            <ArrowLeft className="w-3.5 h-3.5 text-primary" />
+            Back to Home
+          </Link>
         </div>
       </div>
     </main>