diff --git a/static/style.css b/static/style.css
index 7d0e703..f951f49 100644
--- a/static/style.css
+++ b/static/style.css
@@ -5,30 +5,32 @@
 @source '../../internal/**/*.templ';
 
 :root {
-  --bg: #fafaf9;
-  --panel: #f5f5f4;
-  --panel-soft: #e7e5e4;
-  --header: #ffffff;
-  --text: #1c1917;
-  --text-muted: #57534e;
-  --text-faint: #a8a29e;
-  --accent: #0c0a09;
+  color-scheme: light dark;
+
+  --bg: light-dark(#fafaf9, #0c0a09);
+  --panel: light-dark(#f5f5f4, #1c1917);
+  --panel-soft: light-dark(#e7e5e4, #292524);
+  --header: light-dark(#ffffff, #1c1917);
+  --text: light-dark(#1c1917, #e7e5e4);
+  --text-muted: light-dark(#57534e, #a8a29e);
+  --text-faint: light-dark(#a8a29e, #78716c);
+  --accent: light-dark(#0c0a09, #fafaf9);
   --danger: #dc2626;
-  --surface-search: #f5f5f4;
-  --surface-search-focus-border: rgba(12, 10, 9, 0.12);
-  --surface-thumb: #e7e5e4;
-  --surface-input: #ffffff;
-  --surface-input-focus: #ffffff;
-  --surface-tab-hover: #e7e5e4;
-  --surface-tab-active: #1c1917;
-  --text-tab-active: #fafaf9;
-  --surface-select: #ffffff;
-  --surface-search-view-all: #f5f5f4;
-  --text-on-accent: #fafaf9;
-  --overlay-subtle: rgba(0, 0, 0, 0.04);
-  --shadow-subtle: 0 1px 2px rgba(0, 0, 0, 0.04);
-  --shadow-card: 0 4px 12px rgba(0, 0, 0, 0.08);
-  --shadow-card-hover: 0 8px 24px rgba(0, 0, 0, 0.12);
+  --surface-search: light-dark(#f5f5f4, #1c1917);
+  --surface-search-focus-border: light-dark(rgba(12, 10, 9, 0.12), rgba(255, 255, 255, 0.12));
+  --surface-thumb: light-dark(#e7e5e4, #44403c);
+  --surface-input: light-dark(#ffffff, #1c1917);
+  --surface-input-focus: light-dark(#ffffff, #1c1917);
+  --surface-tab-hover: light-dark(#e7e5e4, #292524);
+  --surface-tab-active: light-dark(#1c1917, #fafaf9);
+  --text-tab-active: light-dark(#fafaf9, #0c0a09);
+  --surface-select: light-dark(#ffffff, #1c1917);
+  --surface-search-view-all: light-dark(#f5f5f4, #1c1917);
+  --text-on-accent: light-dark(#fafaf9, #0c0a09);
+  --overlay-subtle: light-dark(rgba(0, 0, 0, 0.04), rgba(255, 255, 255, 0.04));
+  --shadow-subtle: light-dark(0 1px 2px rgba(0, 0, 0, 0.04), 0 1px 2px rgba(0, 0, 0, 0.2));
+  --shadow-card: light-dark(0 4px 12px rgba(0, 0, 0, 0.08), 0 4px 12px rgba(0, 0, 0, 0.3));
+  --shadow-card-hover: light-dark(0 8px 24px rgba(0, 0, 0, 0.12), 0 8px 24px rgba(0, 0, 0, 0.4));
   --space-1: 0.25rem;
   --space-2: 0.5rem;
   --space-3: 0.75rem;
@@ -40,3 +42,11 @@
   --font: 'DM Sans', 'Segoe UI', system-ui, sans-serif;
   --radius: 6px;
 }
+
+[data-theme="light"] {
+  color-scheme: light;
+}
+
+[data-theme="dark"] {
+  color-scheme: dark;
+}
diff --git a/static/theme.ts b/static/theme.ts
new file mode 100644
index 0000000..50ed138
--- /dev/null
+++ b/static/theme.ts
@@ -0,0 +1,80 @@
+type Theme = 'system' | 'light' | 'dark'
+
+const STORAGE_KEY = 'theme'
+
+const getSavedTheme = (): Theme => {
+  const raw = localStorage.getItem(STORAGE_KEY)
+  if (raw === 'light' || raw === 'dark') return raw
+  return 'system'
+}
+
+const getEffectiveTheme = (theme: Theme): 'light' | 'dark' => {
+  if (theme !== 'system') return theme
+  return window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light'
+}
+
+const applyTheme = (theme: Theme): void => {
+  const html = document.documentElement
+  if (theme === 'system') {
+    html.removeAttribute('data-theme')
+  } else {
+    html.setAttribute('data-theme', theme)
+  }
+  localStorage.setItem(STORAGE_KEY, theme)
+  updateToggleButton(theme)
+}
+
+const cycleTheme = (): void => {
+  const current = getSavedTheme()
+  const next: Theme = current === 'system' ? 'light' : current === 'light' ? 'dark' : 'system'
+  applyTheme(next)
+}
+
+const updateToggleButton = (theme: Theme): void => {
+  const btn = document.getElementById('theme-toggle')
+  if (!btn) return
+
+  const label = btn.querySelector('[data-theme-label]') as HTMLElement | null
+  if (label) {
+    label.textContent = theme
+  }
+
+  const svg = btn.querySelector('svg')
+  if (!svg) return
+
+  if (theme === 'light') {
+    svg.innerHTML = '<circle cx="12" cy="12" r="5"/><path d="M12 1v2M12 21v2M4.22 4.22l1.42 1.42M18.36 18.36l1.42 1.42M1 12h2M21 12h2M4.22 19.78l1.42-1.42M18.36 5.64l1.42-1.42"/>'
+    svg.setAttribute('stroke', 'currentColor')
+    svg.setAttribute('fill', 'none')
+  } else if (theme === 'dark') {
+    svg.innerHTML = '<path d="M21 12.79A9 9 0 1 1 11.21 3 7 7 0 0 0 21 12.79z"/>'
+    svg.setAttribute('stroke', 'currentColor')
+    svg.setAttribute('fill', 'none')
+  } else {
+    svg.innerHTML = '<rect x="2" y="3" width="20" height="14" rx="2"/><path d="M8 21h8M12 17v4"/>'
+    svg.setAttribute('stroke', 'currentColor')
+    svg.setAttribute('fill', 'none')
+  }
+}
+
+const initTheme = (): void => {
+  const saved = getSavedTheme()
+  applyTheme(saved)
+
+  const btn = document.getElementById('theme-toggle')
+  if (btn) {
+    btn.addEventListener('click', cycleTheme)
+  }
+
+  window.matchMedia('(prefers-color-scheme: dark)').addEventListener('change', () => {
+    if (getSavedTheme() === 'system') {
+      applyTheme('system')
+    }
+  })
+}
+
+if (document.readyState === 'loading') {
+  document.addEventListener('DOMContentLoaded', initTheme)
+} else {
+  initTheme()
+}
diff --git a/web/shared/layout/layout.templ b/web/shared/layout/layout.templ
index 6c98c6c..1a81a7a 100644
--- a/web/shared/layout/layout.templ
+++ b/web/shared/layout/layout.templ
@@ -12,6 +12,11 @@ templ Layout(title string, showHeader bool) {
 			<link rel="icon" type="image/svg+xml" href="/static/favicon.svg"/>
 			<link rel="stylesheet" href="/dist/tailwind.css"/>
 			<script src="https://unpkg.com/htmx.org@1.9.11" integrity="sha384-0gxUXCCR8yv9FM2b+U3FDbsKthCI66oH5IA9fHppQq9DDMHuMauqq1ZHBpJxQ0J0" crossorigin="anonymous"></script>
+			<script>
+				var t = localStorage.getItem('theme');
+				if (t === 'light' || t === 'dark') document.documentElement.setAttribute('data-theme', t);
+			</script>
+			<script src="/dist/theme.js" defer></script>
 			<script src="/dist/discover.js" defer></script>
 			<script src="/dist/anime.js" defer></script>
 			<script src="/dist/timezone.js" defer></script>
@@ -77,6 +82,18 @@ templ Layout(title string, showHeader bool) {
 									></div>
 							</form>
 						</div>
+						<button
+							id="theme-toggle"
+							type="button"
+							class="inline-flex h-9 w-9 shrink-0 cursor-pointer items-center justify-center border-0 bg-transparent text-(--text-muted) hover:text-(--text)"
+							aria-label="Toggle theme"
+							title="Toggle theme"
+						>
+							<svg class="h-4 w-4" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+								<rect x="2" y="3" width="20" height="14" rx="2"/>
+								<path d="M8 21h8M12 17v4"/>
+							</svg>
+						</button>
 					</div>
 				</header>
 			}