diff --git a/src/components/Header.astro b/src/components/Header.astro
index 856aaa5..9e21bae 100644
--- a/src/components/Header.astro
+++ b/src/components/Header.astro
@@ -1,9 +1,14 @@
+---
+import ThemeSwitch from './ThemeSwitch.astro';
+---
+
 <header>
   <nav class="nav" aria-label="Main menu">
     <div class="nav-left">
-      <a id="logo" class="brand" href="/">Cats Of Tech</a>
+      <a id="logo" class="brand text-primary" href="/">Cats Of Tech</a>
     </div>
     <div class="nav-right">
+      <ThemeSwitch />
       <a class="button outline" href="/submit">Submit a cat</a>
     </div>
   </nav>
@@ -17,4 +22,8 @@
     border-bottom-style: solid;
     border-bottom-color: var(--color-primary);
   }
+
+  a {
+    color: var(--text-grey);
+  }
 </style>
diff --git a/src/components/ThemeSwitch.astro b/src/components/ThemeSwitch.astro
new file mode 100644
index 0000000..3f03c94
--- /dev/null
+++ b/src/components/ThemeSwitch.astro
@@ -0,0 +1,81 @@
+<button
+  id="theme-switch"
+  class="button outline icon-only"
+  title="Switch to dark theme"
+>
+  <svg
+    id="theme-switch-dark-icon"
+    fill="currentColor"
+    viewBox="0 0 20 20"
+    xmlns="http://www.w3.org/2000/svg"
+    ><path d="M17.293 13.293A8 8 0 016.707 2.707a8.001 8.001 0 1010.586 10.586z"
+    ></path></svg
+  >
+  <svg
+    id="theme-switch-light-icon"
+    class="hidden"
+    fill="currentColor"
+    viewBox="0 0 20 20"
+    xmlns="http://www.w3.org/2000/svg"
+    ><path
+      d="M10 2a1 1 0 011 1v1a1 1 0 11-2 0V3a1 1 0 011-1zm4 8a4 4 0 11-8 0 4 4 0 018 0zm-.464 4.95l.707.707a1 1 0 001.414-1.414l-.707-.707a1 1 0 00-1.414 1.414zm2.12-10.607a1 1 0 010 1.414l-.706.707a1 1 0 11-1.414-1.414l.707-.707a1 1 0 011.414 0zM17 11a1 1 0 100-2h-1a1 1 0 100 2h1zm-7 4a1 1 0 011 1v1a1 1 0 11-2 0v-1a1 1 0 011-1zM5.05 6.464A1 1 0 106.465 5.05l-.708-.707a1 1 0 00-1.414 1.414l.707.707zm1.414 8.486l-.707.707a1 1 0 01-1.414-1.414l.707-.707a1 1 0 011.414 1.414zM4 11a1 1 0 100-2H3a1 1 0 000 2h1z"
+      fill-rule="evenodd"
+      clip-rule="evenodd"></path></svg
+  >
+</button>
+
+<script is:inline>
+const themeSwitch = document.getElementById('theme-switch');
+const themeSwitchDarkIcon = document.getElementById('theme-switch-dark-icon');
+const themeSwitchLightIcon = document.getElementById(
+  'theme-switch-light-icon'
+);
+
+if (
+  !localStorage.getItem('theme') &&
+  window.matchMedia &&
+  window.matchMedia('(prefers-color-scheme: dark)').matches
+) {
+  localStorage.setItem('theme', 'dark');
+}
+
+if (localStorage.getItem('theme') === 'dark') {
+  document.body.classList.add('dark');
+  themeSwitchLightIcon.classList.remove('hidden');
+  themeSwitchDarkIcon.classList.add('hidden');
+  themeSwitch.setAttribute('title', 'Switch to light theme');
+}
+
+themeSwitch.addEventListener('click', () => {
+  const currentTheme = localStorage.getItem('theme');
+
+  if (currentTheme === 'dark') {
+    localStorage.setItem('theme', 'light');
+    document.body.classList.remove('dark');
+    themeSwitchLightIcon.classList.add('hidden');
+    themeSwitchDarkIcon.classList.remove('hidden');
+    themeSwitch.setAttribute('title', 'Switch to dark theme');
+  } else {
+    localStorage.setItem('theme', 'dark');
+    document.body.classList.add('dark');
+    themeSwitchLightIcon.classList.remove('hidden');
+    themeSwitchDarkIcon.classList.add('hidden');
+    themeSwitch.setAttribute('title', 'Switch to light theme');
+  }
+});
+</script>
+
+<style>
+  svg {
+    width: var(--font-size);
+    color: var(--font-color);
+  }
+
+  #theme-switch {
+    color: var(--font-color);
+  }
+
+  .hidden {
+    display: none;
+  }
+</style>