Add ThemeToggle component

src/components/ArticleSearchWrapper.astro

@@ -7,4 +7,4 @@ const articles = (await getCollection("blog")).sort(
 );
 ---
 
-<ArticleSearch client:load {articles} />
+<ArticleSearch client:only="svelte" {articles} />

src/components/Dropdown.svelte

@@ -1,7 +1,7 @@
 <script lang="ts">
     export let shortcut: string;
 
-    const possibleShortcuts = ["S", "T"];
+    const possibleShortcuts = ["S", "C", "T"];
 
     let detailsElement: HTMLDetailsElement;
     let summaryElement: HTMLElement;

src/components/Head.astro

@@ -11,4 +11,8 @@ const { title, description } = Astro.props;
   <title>{title}</title>
   <meta name="author" content="Your Name" />
   <meta name="description" content={description} />
+  <script is:inline>
+    const storedTheme = localStorage.getItem("theme");
+    document.documentElement.classList = storedTheme;
+  </script>
 </head>

src/components/Nav.astro

@@ -1,5 +1,6 @@
 ---
 import ArticleSearchWrapper from "../components/ArticleSearchWrapper.astro";
+import ThemeToggle from "../components/ThemeToggle.svelte";
 ---
 
 <nav>
@@ -9,6 +10,7 @@ import ArticleSearchWrapper from "../components/ArticleSearchWrapper.astro";
     </a>
     <slot />
     <ArticleSearchWrapper />
+    <ThemeToggle client:only="svelte" />
   </div>
 </nav>
 

src/components/TableOfContents.svelte

@@ -4,19 +4,17 @@
     export let headings: MarkdownHeading[] = [];
 
     import Dropdown from "./Dropdown.svelte";
-
-    let dropdown;
 </script>
 
-<Dropdown shortcut="T" bind:this={dropdown}>
+<Dropdown shortcut="C">
     <svg slot="icon" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="currentColor">
-      <title>Table of contents (Shift + t)</title>
+      <title>Table of contents (Shift + c)</title>
       <path fill-rule="evenodd" d="M2.625 6.75a1.125 1.125 0 112.25 0 1.125 1.125 0 01-2.25 0zm4.875 0A.75.75 0 018.25 6h12a.75.75 0 010 1.5h-12a.75.75 0 01-.75-.75zM2.625 12a1.125 1.125 0 112.25 0 1.125 1.125 0 01-2.25 0zM7.5 12a.75.75 0 01.75-.75h12a.75.75 0 010 1.5h-12A.75.75 0 017.5 12zm-4.875 5.25a1.125 1.125 0 112.25 0 1.125 1.125 0 01-2.25 0zm4.875 0a.75.75 0 01.75-.75h12a.75.75 0 010 1.5h-12a.75.75 0 01-.75-.75z" clip-rule="evenodd" />
     </svg>
     <ul>
         {#each headings.filter(({ depth }) => depth === 2) as { slug, text }}
             <li>
-                <a href="#{slug}" on:click={dropdown.closeMenu}>{text}</a>
+                <a href="#{slug}">{text}</a>
             </li>
         {/each}
     </ul>

src/components/ThemeToggle.svelte

@@ -0,0 +1,47 @@
+<script lang="ts">
+  import Dropdown from "./Dropdown.svelte";
+
+  let themeOptions = ["System", "Light", "Dark"];
+
+  let theme = "System";
+
+  function loadTheme() {
+    theme = localStorage.getItem("theme");
+  }
+
+  function saveTheme() {
+    localStorage.setItem("theme", theme);
+  }
+
+  loadTheme();
+
+  $: document.documentElement.classList = theme;
+</script>
+
+<Dropdown shortcut="T">
+  <svg slot="icon" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="currentColor" class="w-6 h-6">
+    <title>Toggle theme (Shift + t)</title>
+    <path fill-rule="evenodd" d="M2.25 5.25a3 3 0 013-3h13.5a3 3 0 013 3V15a3 3 0 01-3 3h-3v.257c0 .597.237 1.17.659 1.591l.621.622a.75.75 0 01-.53 1.28h-9a.75.75 0 01-.53-1.28l.621-.622a2.25 2.25 0 00.659-1.59V18h-3a3 3 0 01-3-3V5.25zm1.5 0v7.5a1.5 1.5 0 001.5 1.5h13.5a1.5 1.5 0 001.5-1.5v-7.5a1.5 1.5 0 00-1.5-1.5H5.25a1.5 1.5 0 00-1.5 1.5z" clip-rule="evenodd" />
+  </svg>
+  <div class="theme-toggle">
+    {#each themeOptions as option, index}
+      <div>
+        <input type="radio" id="theme-{option}" name="theme" value={option} bind:group={theme} on:change={saveTheme} />
+        <label for="theme-{option}">{option}</label>
+      </div>
+    {/each}
+  </div>
+</Dropdown>
+
+<style>
+  .theme-toggle {
+    position: absolute;
+    inset-inline-end: 0;
+    inset-block-start: var(--nav-height);
+    background-color: var(--background-color);
+    border: var(--standard-border);
+    padding: 1rem;
+    display: grid;
+    gap: 0.5rem;
+  }
+</style>