diff --git a/src/app/dock/error.tsx b/src/app/dock/error.tsx
new file mode 100644
index 0000000..8514a1a
--- /dev/null
+++ b/src/app/dock/error.tsx
@@ -0,0 +1,57 @@
+'use client';
+
+import { useEffect } from 'react';
+import Link from 'next/link';
+import { GiSinkingShip } from 'react-icons/gi';
+import { cn } from '@/lib/utils/cn';
+
+interface DockErrorProps {
+  error: Error & { digest?: string };
+  unstable_retry: () => void;
+}
+
+function DockError({ error, unstable_retry }: DockErrorProps) {
+  useEffect(() => {
+    console.error(error);
+  }, [error]);
+
+  return (
+    <main className={styles.root}>
+      <GiSinkingShip className={styles.icon} aria-hidden="true" />
+      <h1 className={styles.title}>We’ve sprung a leak</h1>
+      <p className={styles.description}>
+        We hit rough water loading your dock. Try again, or head back.
+      </p>
+      <div className={styles.actions}>
+        <button type="button" onClick={() => unstable_retry()} className={styles.retry}>
+          Try again
+        </button>
+        <Link href="/dock" className={styles.back}>
+          Back to your dock
+        </Link>
+      </div>
+    </main>
+  );
+}
+
+const styles = {
+  root: cn(
+    'text-gd-text flex min-h-[70vh] flex-col items-center justify-center gap-4 px-6 text-center',
+  ),
+  icon: cn('text-gd-error text-7xl'),
+  title: cn('text-3xl font-semibold'),
+  description: cn('text-gd-muted max-w-md text-balance'),
+  actions: cn('mt-2 flex flex-wrap items-center justify-center gap-3'),
+  retry: cn(
+    'bg-gd-accent text-gd-bg hover:bg-gd-accent-glow active:translate-y-px',
+    'focus-visible:outline-gd-accent focus-visible:outline-2 focus-visible:outline-offset-2',
+    'rounded-lg px-5 py-2.5 text-sm font-medium transition-colors',
+  ),
+  back: cn(
+    'text-gd-muted hover:text-gd-text active:translate-y-px',
+    'focus-visible:outline-gd-accent focus-visible:outline-2 focus-visible:outline-offset-2',
+    'rounded-lg px-5 py-2.5 text-sm font-medium transition-colors',
+  ),
+};
+
+export default DockError;
diff --git a/src/app/dock/not-found.tsx b/src/app/dock/not-found.tsx
new file mode 100644
index 0000000..1c0c3c0
--- /dev/null
+++ b/src/app/dock/not-found.tsx
@@ -0,0 +1,39 @@
+import Link from 'next/link';
+import { GiBoatHorizon } from 'react-icons/gi';
+import { cn } from '@/lib/utils/cn';
+
+function DockNotFound() {
+  return (
+    <main className={styles.root}>
+      <GiBoatHorizon className={styles.icon} aria-hidden="true" />
+      <div className={styles.heading}>
+        <p className={styles.code}>404</p>
+        <h1 className={styles.title}>Project not found</h1>
+      </div>
+      <p className={styles.description}>
+        That project drifted off the map — it may have been removed, or the link’s wrong.
+      </p>
+      <Link href="/dock" className={styles.action}>
+        Back to your dock
+      </Link>
+    </main>
+  );
+}
+
+const styles = {
+  root: cn(
+    'text-gd-text flex min-h-[70vh] flex-col items-center justify-center gap-4 px-6 text-center',
+  ),
+  icon: cn('text-gd-muted text-7xl'),
+  heading: cn('flex flex-col items-center gap-1'),
+  code: cn('text-gd-accent text-sm font-semibold tracking-[0.2em]'),
+  title: cn('text-3xl font-semibold'),
+  description: cn('text-gd-muted max-w-md text-balance'),
+  action: cn(
+    'bg-gd-accent text-gd-bg hover:bg-gd-accent-glow active:translate-y-px',
+    'focus-visible:outline-gd-accent focus-visible:outline-2 focus-visible:outline-offset-2',
+    'mt-2 rounded-lg px-5 py-2.5 text-sm font-medium transition-colors',
+  ),
+};
+
+export default DockNotFound;
diff --git a/src/app/error.tsx b/src/app/error.tsx
new file mode 100644
index 0000000..9e388bc
--- /dev/null
+++ b/src/app/error.tsx
@@ -0,0 +1,45 @@
+'use client';
+
+import { useEffect } from 'react';
+import { GiSinkingShip } from 'react-icons/gi';
+import { cn } from '@/lib/utils/cn';
+
+interface RootErrorProps {
+  error: Error & { digest?: string };
+  unstable_retry: () => void;
+}
+
+function RootError({ error, unstable_retry }: RootErrorProps) {
+  useEffect(() => {
+    console.error(error);
+  }, [error]);
+
+  return (
+    <main className={styles.root}>
+      <GiSinkingShip className={styles.icon} aria-hidden="true" />
+      <h1 className={styles.title}>We’ve sprung a leak</h1>
+      <p className={styles.description}>
+        Something went wrong on deck. Try again — if it keeps happening, check back later.
+      </p>
+      <button type="button" onClick={() => unstable_retry()} className={styles.action}>
+        Try again
+      </button>
+    </main>
+  );
+}
+
+const styles = {
+  root: cn(
+    'bg-gd-bg text-gd-text flex min-h-screen flex-col items-center justify-center gap-4 px-6 text-center',
+  ),
+  icon: cn('text-gd-error text-7xl'),
+  title: cn('text-3xl font-semibold'),
+  description: cn('text-gd-muted max-w-md text-balance'),
+  action: cn(
+    'bg-gd-accent text-gd-bg hover:bg-gd-accent-glow active:translate-y-px',
+    'focus-visible:outline-gd-accent focus-visible:outline-2 focus-visible:outline-offset-2',
+    'mt-2 rounded-lg px-5 py-2.5 text-sm font-medium transition-colors',
+  ),
+};
+
+export default RootError;
diff --git a/src/app/global-error.tsx b/src/app/global-error.tsx
new file mode 100644
index 0000000..b37b558
--- /dev/null
+++ b/src/app/global-error.tsx
@@ -0,0 +1,50 @@
+'use client';
+
+import { useEffect } from 'react';
+import { GiSinkingShip } from 'react-icons/gi';
+import { cn } from '@/lib/utils/cn';
+import './globals.css';
+
+interface GlobalErrorProps {
+  error: Error & { digest?: string };
+  unstable_retry: () => void;
+}
+
+function GlobalError({ error, unstable_retry }: GlobalErrorProps) {
+  useEffect(() => {
+    console.error(error);
+  }, [error]);
+
+  return (
+    <html lang="en">
+      <body className={styles.body}>
+        <title>Something went wrong · GhostDock</title>
+        <main className={styles.root}>
+          <GiSinkingShip className={styles.icon} aria-hidden="true" />
+          <h1 className={styles.title}>We’ve sprung a leak</h1>
+          <p className={styles.description}>
+            GhostDock hit an unexpected error. Try again in a moment.
+          </p>
+          <button type="button" onClick={() => unstable_retry()} className={styles.action}>
+            Try again
+          </button>
+        </main>
+      </body>
+    </html>
+  );
+}
+
+const styles = {
+  body: cn('bg-gd-bg text-gd-text'),
+  root: cn('flex min-h-screen flex-col items-center justify-center gap-4 px-6 text-center'),
+  icon: cn('text-gd-error text-7xl'),
+  title: cn('text-3xl font-semibold'),
+  description: cn('text-gd-muted max-w-md text-balance'),
+  action: cn(
+    'bg-gd-accent text-gd-bg hover:bg-gd-accent-glow active:translate-y-px',
+    'focus-visible:outline-gd-accent focus-visible:outline-2 focus-visible:outline-offset-2',
+    'mt-2 rounded-lg px-5 py-2.5 text-sm font-medium transition-colors',
+  ),
+};
+
+export default GlobalError;
diff --git a/src/app/not-found.tsx b/src/app/not-found.tsx
new file mode 100644
index 0000000..a490b72
--- /dev/null
+++ b/src/app/not-found.tsx
@@ -0,0 +1,39 @@
+import Link from 'next/link';
+import { GiBoatHorizon } from 'react-icons/gi';
+import { cn } from '@/lib/utils/cn';
+
+function RootNotFound() {
+  return (
+    <main className={styles.root}>
+      <GiBoatHorizon className={styles.icon} aria-hidden="true" />
+      <div className={styles.heading}>
+        <p className={styles.code}>404</p>
+        <h1 className={styles.title}>Lost in the fog</h1>
+      </div>
+      <p className={styles.description}>
+        This page drifted off the map. Let’s get you back to shore.
+      </p>
+      <Link href="/" className={styles.action}>
+        Return home
+      </Link>
+    </main>
+  );
+}
+
+const styles = {
+  root: cn(
+    'bg-gd-bg text-gd-text flex min-h-screen flex-col items-center justify-center gap-4 px-6 text-center',
+  ),
+  icon: cn('text-gd-muted text-7xl'),
+  heading: cn('flex flex-col items-center gap-1'),
+  code: cn('text-gd-accent text-sm font-semibold tracking-[0.2em]'),
+  title: cn('text-3xl font-semibold'),
+  description: cn('text-gd-muted max-w-md text-balance'),
+  action: cn(
+    'bg-gd-accent text-gd-bg hover:bg-gd-accent-glow active:translate-y-px',
+    'focus-visible:outline-gd-accent focus-visible:outline-2 focus-visible:outline-offset-2',
+    'mt-2 rounded-lg px-5 py-2.5 text-sm font-medium transition-colors',
+  ),
+};
+
+export default RootNotFound;
diff --git a/src/app/p/[slug]/error.tsx b/src/app/p/[slug]/error.tsx
new file mode 100644
index 0000000..136401e
--- /dev/null
+++ b/src/app/p/[slug]/error.tsx
@@ -0,0 +1,46 @@
+'use client';
+
+import { useEffect } from 'react';
+import { cn } from '@/lib/utils/cn';
+
+// Applies the visitor's saved theme before first paint, so there is no light/dark flash.
+const themeScript = `(function(){try{var t=localStorage.getItem('pp-theme');if(t==='light'||t==='dark'){document.documentElement.setAttribute('data-pp-theme',t);}}catch(e){}})();`;
+
+interface PublicErrorProps {
+  error: Error & { digest?: string };
+  unstable_retry: () => void;
+}
+
+function PublicError({ error, unstable_retry }: PublicErrorProps) {
+  useEffect(() => {
+    console.error(error);
+  }, [error]);
+
+  return (
+    <>
+      <script dangerouslySetInnerHTML={{ __html: themeScript }} />
+      <main className={styles.root}>
+        <h1 className={styles.title}>Something went wrong</h1>
+        <p className={styles.description}>This page couldn’t be loaded. Try again in a moment.</p>
+        <button type="button" onClick={() => unstable_retry()} className={styles.action}>
+          Try again
+        </button>
+      </main>
+    </>
+  );
+}
+
+const styles = {
+  root: cn(
+    'bg-pp-paper text-pp-ink flex min-h-screen flex-col items-center justify-center gap-4 px-6 text-center',
+  ),
+  title: cn('text-pp-ink-strong text-3xl font-semibold'),
+  description: cn('text-pp-muted max-w-md text-balance'),
+  action: cn(
+    'border-pp-rule text-pp-ink hover:bg-pp-paper-2 active:translate-y-px',
+    'focus-visible:outline-pp-focus focus-visible:outline-2 focus-visible:outline-offset-2',
+    'mt-2 rounded-lg border px-5 py-2.5 text-sm font-medium transition-colors',
+  ),
+};
+
+export default PublicError;
diff --git a/src/app/p/[slug]/loading.tsx b/src/app/p/[slug]/loading.tsx
new file mode 100644
index 0000000..ffd11b9
--- /dev/null
+++ b/src/app/p/[slug]/loading.tsx
@@ -0,0 +1,40 @@
+import { cn } from '@/lib/utils/cn';
+
+// Applies the visitor's saved theme before first paint, so there is no light/dark flash.
+const themeScript = `(function(){try{var t=localStorage.getItem('pp-theme');if(t==='light'||t==='dark'){document.documentElement.setAttribute('data-pp-theme',t);}}catch(e){}})();`;
+
+function PublicLoading() {
+  return (
+    <>
+      <script dangerouslySetInnerHTML={{ __html: themeScript }} />
+      <main className={styles.root} role="status" aria-label="Loading project">
+        <span className={styles.srOnly}>Loading project…</span>
+        <div className={styles.inner} aria-hidden="true">
+          <div className={styles.title} />
+          <div className={styles.lines}>
+            <div className={styles.line} />
+            <div className={cn(styles.line, 'w-2/3')} />
+          </div>
+          <div className={styles.badges}>
+            <div className={styles.badge} />
+            <div className={styles.badge} />
+            <div className={styles.badge} />
+          </div>
+        </div>
+      </main>
+    </>
+  );
+}
+
+const styles = {
+  root: cn('bg-pp-paper min-h-screen'),
+  srOnly: cn('sr-only'),
+  inner: cn('mx-auto flex max-w-2xl flex-col gap-6 px-5 py-16 motion-safe:animate-pulse sm:py-20'),
+  title: cn('bg-pp-rule h-10 w-2/3 rounded-md'),
+  lines: cn('flex flex-col gap-2.5'),
+  line: cn('bg-pp-rule h-4 w-full rounded'),
+  badges: cn('mt-2 flex gap-2'),
+  badge: cn('bg-pp-rule h-7 w-20 rounded-full'),
+};
+
+export default PublicLoading;
diff --git a/src/app/p/[slug]/not-found.tsx b/src/app/p/[slug]/not-found.tsx
new file mode 100644
index 0000000..190302c
--- /dev/null
+++ b/src/app/p/[slug]/not-found.tsx
@@ -0,0 +1,42 @@
+import Link from 'next/link';
+import { cn } from '@/lib/utils/cn';
+
+// Applies the visitor's saved theme before first paint, so there is no light/dark flash.
+const themeScript = `(function(){try{var t=localStorage.getItem('pp-theme');if(t==='light'||t==='dark'){document.documentElement.setAttribute('data-pp-theme',t);}}catch(e){}})();`;
+
+function PublicNotFound() {
+  return (
+    <>
+      <script dangerouslySetInnerHTML={{ __html: themeScript }} />
+      <main className={styles.root}>
+        <div className={styles.heading}>
+          <p className={styles.code}>404</p>
+          <h1 className={styles.title}>Project not found</h1>
+        </div>
+        <p className={styles.description}>
+          This project page doesn’t exist, or it hasn’t been published yet.
+        </p>
+        <Link href="/" className={styles.action}>
+          Go to GhostDock
+        </Link>
+      </main>
+    </>
+  );
+}
+
+const styles = {
+  root: cn(
+    'bg-pp-paper text-pp-ink flex min-h-screen flex-col items-center justify-center gap-4 px-6 text-center',
+  ),
+  heading: cn('flex flex-col items-center gap-1'),
+  code: cn('text-pp-muted text-sm font-semibold tracking-[0.2em]'),
+  title: cn('text-pp-ink-strong text-3xl font-semibold'),
+  description: cn('text-pp-muted max-w-md text-balance'),
+  action: cn(
+    'border-pp-rule text-pp-ink hover:bg-pp-paper-2 active:translate-y-px',
+    'focus-visible:outline-pp-focus focus-visible:outline-2 focus-visible:outline-offset-2',
+    'mt-2 rounded-lg border px-5 py-2.5 text-sm font-medium transition-colors',
+  ),
+};
+
+export default PublicNotFound;