diff --git a/src/components/Icon.astro b/src/components/Icon.astro
new file mode 100644
index 0000000..4e63cec
--- /dev/null
+++ b/src/components/Icon.astro
@@ -0,0 +1,23 @@
+---
+export interface Props {
+    name: string,
+};
+
+const { name } = Astro.props;
+
+const icons = import.meta.glob<{string: string}>('@components/icons/*.svg', { query: '?raw', import: 'default' });
+const path = `/src/components/icons/${name}.svg`;
+if (icons[path] === undefined) {
+    throw new Error(`Icon ${name} does not exist.`);
+}
+const icon = await icons[path]();
+---
+
+<Fragment set:html={icon} />
+
+<style>
+    svg {
+        width: 100%;
+        height: 100%;
+    }
+</style>
diff --git a/src/components/ThemeSwitcher.astro b/src/components/ThemeSwitcher.astro
new file mode 100644
index 0000000..cc22c19
--- /dev/null
+++ b/src/components/ThemeSwitcher.astro
@@ -0,0 +1,73 @@
+---
+import Icon from '@components/Icon.astro';
+---
+
+
+<div class="theme-switcher">
+    <button id="switch-to-dark">
+        <Icon name="sun" />
+    </button>
+    <button id="switch-to-light">
+        <Icon name="moon" />
+    </button>
+</div>
+
+
+<style>
+.theme-switcher {
+    position: relative;
+    isolation: isolate;
+    width: 1.5rem;
+    height: 1.5rem;
+
+    transform: translateY(0.1rem);
+}
+
+button {
+    position: absolute;
+    inset: 0;
+
+    background-color: transparent;
+    padding: 0;
+    color: var(--nav-link-color);
+    border: none;
+
+    &:hover {
+        cursor: pointer;
+        color: var(--accent-color);
+    }
+
+    /* hide by default, i.e. if JS isn't enabled and the data-theme attribute didn't get set, */
+    visibility: hidden;
+    opacity: 0;
+    transition:
+        color 0.2s ease,
+        opacity 0.5s ease,
+        transform 0.5s ease;
+}
+
+:global(html[data-theme="light"]) button#switch-to-dark {
+    opacity: 1;
+    visibility: visible;
+    transform: rotate(360deg);
+    /* whichever one is currently active should be on top */
+    z-index: 10;
+}
+:global(html[data-theme="dark"]) button#switch-to-light {
+    opacity: 1;
+    visibility: visible;
+    transform: rotate(-360deg);
+    z-index: 10;
+}
+</style>
+
+<script>
+document.getElementById('switch-to-dark')?.addEventListener('click', () => {
+    localStorage.setItem('theme-preference', 'dark');
+    document.documentElement.dataset.theme = 'dark';
+});
+document.getElementById('switch-to-light')?.addEventListener('click', () => {
+    localStorage.setItem('theme-preference', 'light');
+    document.documentElement.dataset.theme = 'light';
+})
+</script>
diff --git a/src/components/icons/moon.svg b/src/components/icons/moon.svg
new file mode 100644
index 0000000..4691de4
--- /dev/null
+++ b/src/components/icons/moon.svg
@@ -0,0 +1,10 @@
+<svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor">
+  <path stroke-linecap="round" stroke-linejoin="round" d="M21.752 15.002A9.72 9.72 0 0 1 18 15.75c-5.385 0-9.75-4.365-9.75-9.75 0-1.33.266-2.597.748-3.752A9.753 9.753 0 0 0 3 11.25C3 16.635 7.365 21 12.75 21a9.753 9.753 0 0 0 9.002-5.998Z" />
+</svg>
+
+<style>
+svg {
+    width: 100%;
+    height: 100%;
+}
+</style>
diff --git a/src/components/icons/sun.svg b/src/components/icons/sun.svg
new file mode 100644
index 0000000..6c72f4c
--- /dev/null
+++ b/src/components/icons/sun.svg
@@ -0,0 +1,3 @@
+<svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor">
+  <path stroke-linecap="round" stroke-linejoin="round" d="M12 3v2.25m6.364.386-1.591 1.591M21 12h-2.25m-.386 6.364-1.591-1.591M12 18.75V21m-4.773-4.227-1.591 1.591M5.25 12H3m4.227-4.773L5.636 5.636M15.75 12a3.75 3.75 0 1 1-7.5 0 3.75 3.75 0 0 1 7.5 0Z" />
+</svg>
diff --git a/src/layouts/BaseLayout.astro b/src/layouts/BaseLayout.astro
index 9f010af..25c24b8 100644
--- a/src/layouts/BaseLayout.astro
+++ b/src/layouts/BaseLayout.astro
@@ -2,6 +2,7 @@
 import '@styles/main.css';
 import '@fontsource-variable/baskervville';
 import '@fontsource-variable/baskervville-sc';
+import ThemeSwitcher from '@components/ThemeSwitcher.astro';
 ---
 
 <html lang="en">
@@ -11,9 +12,12 @@ import '@fontsource-variable/baskervville-sc';
 
         <!-- avoid FOUC by setting the color schme here in the header -->
         <script>
-        const pref = localStorage.getItem('theme-preference');
-        if (pref) {
-            document.documentElement.dataset.theme = pref;
+        const explicitPref = localStorage.getItem('theme-preference');
+        if (explicitPref) {
+            document.documentElement.dataset.theme = explicitPref;
+        } else {
+            const isLight = window.matchMedia('(prefers-color-scheme: light)').matches;
+            document.documentElement.dataset.theme = isLight ? 'light' : 'dark';
         }
         </script>
 
@@ -55,12 +59,19 @@ import '@fontsource-variable/baskervville-sc';
                     }
                 }
             }
+
+            .switcher-container {
+                align-self: center;
+            }
         </style>
     </head>
     <body>
         <header>
             <nav>
                 <a href="/" class="home" data-astro-prefetch>Joe's Blog</a>
+                <div class="switcher-container">
+                    <ThemeSwitcher />
+                </div>
                 <a href="/posts" data-astro-prefetch>Posts</a>
                 <a href="/about" data-astro-prefetch>About</a>
             </nav>
diff --git a/src/styles/vars.css b/src/styles/vars.css
index 83c178b..5a5fc55 100644
--- a/src/styles/vars.css
+++ b/src/styles/vars.css
@@ -51,6 +51,7 @@
 
     &:not([data-theme="light"]) {
         @media(prefers-color-scheme: dark) {
+            color-scheme: dark;
             --bg-color: var(--dark-bg-color);
             --content-color: var(--dark-content-color);
             --content-color-faded: var(--dark-content-color-faded);