diff --git a/public/assets/js/detect-theme.min.js b/public/assets/js/detect-theme.min.js
new file mode 100644
index 0000000..767e086
--- /dev/null
+++ b/public/assets/js/detect-theme.min.js
@@ -0,0 +1 @@
+window.theme=(()=>{const e=localStorage.getItem("theme");if(e&&("dark"===e||"light"===e))return e;const t=window.matchMedia("(prefers-color-scheme: dark)").matches;return t?"dark":"light"})(),document.documentElement.setAttribute("data-theme",window.theme),window.matchMedia("(prefers-color-scheme: dark)").addEventListener("change",({matches:e})=>{window.theme=e?"dark":"light",localStorage.setItem("theme",window.theme),document.documentElement.setAttribute("data-theme",window.theme)});
\ No newline at end of file
diff --git a/src/components/BaseHead.astro b/src/components/BaseHead.astro
index 842e33b..9038dc1 100644
--- a/src/components/BaseHead.astro
+++ b/src/components/BaseHead.astro
@@ -21,5 +21,5 @@
 </title>
 <meta name='title' content={title} />
 <meta name='description' content={description || SITE_METADATA.description} />
-<script is:inline src='assets/js/detect-theme.js' />
+<script is:inline src='assets/js/detect-theme.min.js' />
 <slot></slot>
\ No newline at end of file
diff --git a/src/components/Header/Header.astro b/src/components/Header/Header.astro
index 13c833b..520bd36 100644
--- a/src/components/Header/Header.astro
+++ b/src/components/Header/Header.astro
@@ -1,12 +1,13 @@
 ---
-import './Header.scss';
-import { SITE_METADATA } from '@root/config';
-import ThemeSwitcher from '@components/ThemeSwticher';
-import { Icon } from 'astro-icon';
-import NavToggle from './NavToggle';
+	import './Header.scss';
+	import { SITE_METADATA } from '@root/config';
+	import ThemeSwitcher from '@components/ThemeSwticher';
+	import { Icon } from 'astro-icon';
+	import { removeSlashes } from '@utils/string'
+	import NavToggle from './NavToggle';
 
-const { name, nav, contacts } = SITE_METADATA;
-const { pathname } = Astro.canonicalURL;
+	const { name, nav, contacts } = SITE_METADATA;
+	const { pathname } = Astro.canonicalURL;
 ---
 
 <header class='header'>
@@ -17,11 +18,11 @@ const { pathname } = Astro.canonicalURL;
 		<nav class='header__nav'>
 			<ul class='header__nav-links'>
 				{nav.map((link) => (
-					<li>
-						<a class={pathname.includes(link.url) && 'active'} href={link.url}>
-							{link.name}
-						</a>
-					</li>
+				<li>
+					<a class={removeSlashes(pathname)===removeSlashes(link.url) && 'active' } href={link.url}>
+						{link.name}
+					</a>
+				</li>
 				))}
 			</ul>
 			<div class='header__nav-contacts'>
@@ -42,4 +43,4 @@ const { pathname } = Astro.canonicalURL;
 		</nav>
 		<NavToggle client:visible />
 	</div>
-</header>
+</header>
\ No newline at end of file
diff --git a/src/pages/404.astro b/src/pages/404.astro
new file mode 100644
index 0000000..d12a21c
--- /dev/null
+++ b/src/pages/404.astro
@@ -0,0 +1,10 @@
+---
+  import PageLayout from '@layouts/default.astro'
+---
+
+<PageLayout title="404" showPageHeading={false}>
+  <div class="container">
+    <h1 style="font-size:var(--font-size-5xl);">404</h1>
+    <p>Страницу которую вы пытаетесь найти не существует.</p>
+  </div>
+</PageLayout>
\ No newline at end of file
diff --git a/src/utils/string.ts b/src/utils/string.ts
new file mode 100644
index 0000000..23d213a
--- /dev/null
+++ b/src/utils/string.ts
@@ -0,0 +1,3 @@
+export function removeSlashes(string: string): string {
+	return string.replaceAll('/', '');
+}