diff --git a/src/lib/components/SearchSelect.svelte b/src/lib/components/SearchSelect.svelte
new file mode 100644
index 0000000..e6e7b37
--- /dev/null
+++ b/src/lib/components/SearchSelect.svelte
@@ -0,0 +1,170 @@
+<script lang="ts">
+	import { tick } from "svelte";
+
+	type SearchSelectOption = {
+		value: string;
+		label: string;
+		searchText?: string;
+	};
+
+	let {
+		id,
+		value = $bindable(""),
+		options,
+		placeholder = "Select...",
+		searchPlaceholder = "Search...",
+		emptyMessage = "No matches",
+	}: {
+		id: string;
+		value?: string;
+		options: SearchSelectOption[];
+		placeholder?: string;
+		searchPlaceholder?: string;
+		emptyMessage?: string;
+	} = $props();
+
+	let open = $state(false);
+	let query = $state("");
+	let highlight = $state(0);
+	let searchInput: HTMLInputElement | undefined = $state();
+	let listEl: HTMLDivElement | undefined = $state();
+
+	const selected = $derived(options.find((option) => option.value === value));
+	const filtered = $derived.by(() => {
+		const q = query.trim().toLowerCase();
+		if (!q) return options;
+		return options.filter((option) => {
+			const haystack = (option.searchText ?? option.label).toLowerCase();
+			return haystack.includes(q);
+		});
+	});
+
+	async function openMenu() {
+		open = true;
+		query = "";
+		await tick();
+		const selectedIndex = filtered.findIndex((option) => option.value === value);
+		highlight = selectedIndex >= 0 ? selectedIndex : 0;
+		searchInput?.focus();
+	}
+
+	function closeMenu() {
+		open = false;
+		query = "";
+	}
+
+	function choose(optionValue: string) {
+		value = optionValue;
+		closeMenu();
+	}
+
+	function moveHighlight(delta: number) {
+		if (filtered.length === 0) return;
+		if (highlight < 0 || highlight >= filtered.length) {
+			highlight = delta > 0 ? 0 : filtered.length - 1;
+		} else {
+			highlight = (highlight + delta + filtered.length) % filtered.length;
+		}
+		const item = listEl?.children[highlight + 1] as HTMLElement | undefined;
+		item?.scrollIntoView({ block: "nearest" });
+	}
+
+	function onSearchKeydown(event: KeyboardEvent) {
+		if (event.key === "ArrowDown") {
+			event.preventDefault();
+			moveHighlight(1);
+		} else if (event.key === "ArrowUp") {
+			event.preventDefault();
+			moveHighlight(-1);
+		} else if (event.key === "Enter") {
+			event.preventDefault();
+			const option = filtered[highlight];
+			if (option) choose(option.value);
+		} else if (event.key === "Escape") {
+			event.preventDefault();
+			closeMenu();
+		}
+	}
+</script>
+
+<div class="relative">
+	<button
+		{id}
+		type="button"
+		class="border-rule text-ink focus:border-primary bg-surface flex w-full items-center justify-between gap-2 rounded-sm border px-3 py-2.5 text-left text-sm transition-colors outline-none"
+		aria-haspopup="listbox"
+		aria-expanded={open}
+		onclick={() => (open ? closeMenu() : openMenu())}
+	>
+		<span class="min-w-0 flex-1 truncate {selected ? '' : 'text-faint'}"
+			>{selected?.label ?? placeholder}</span
+		>
+		<svg
+			class="text-muted h-3.5 w-3.5 shrink-0 transition-transform {open ? 'rotate-180' : ''}"
+			viewBox="0 0 24 24"
+			fill="none"
+			stroke="currentColor"
+			stroke-width="1.5"
+			aria-hidden="true"
+		>
+			<path stroke-linecap="square" d="m6 9 6 6 6-6" />
+		</svg>
+	</button>
+
+	{#if open}
+		<button
+			type="button"
+			class="fixed inset-0 z-10 cursor-default"
+			aria-label="Close menu"
+			onclick={closeMenu}
+		></button>
+		<div
+			class="border-rule bg-surface absolute z-20 mt-1 w-full overflow-hidden rounded-sm border shadow-lg"
+		>
+			<div class="border-rule border-b p-1.5">
+				<input
+					bind:this={searchInput}
+					type="search"
+					bind:value={query}
+					placeholder={searchPlaceholder}
+					aria-label={searchPlaceholder}
+					class="field py-1.5 text-sm"
+					onkeydown={onSearchKeydown}
+					oninput={() => (highlight = 0)}
+				/>
+			</div>
+			<div bind:this={listEl} role="listbox" class="max-h-56 overflow-y-auto py-1">
+				<button
+					type="button"
+					role="option"
+					aria-selected={value === ""}
+					class="block w-full px-3 py-2 text-left text-sm {value === ''
+						? 'text-primary'
+						: 'text-muted hover:text-ink'}"
+					onmouseenter={() => (highlight = -1)}
+					onclick={() => choose("")}
+				>
+					{placeholder}
+				</button>
+				{#each filtered as option, index (option.value)}
+					<button
+						type="button"
+						role="option"
+						aria-selected={option.value === value}
+						class="block w-full px-3 py-2 text-left text-sm {index === highlight ||
+						option.value === value
+							? 'text-primary'
+							: 'text-ink hover:text-primary'}"
+						onmouseenter={() => (highlight = index)}
+						onclick={() => choose(option.value)}
+					>
+						{option.label}
+					</button>
+				{/each}
+				{#if filtered.length === 0}
+					<p class="text-muted px-3 py-2 text-sm">{emptyMessage}</p>
+				{/if}
+			</div>
+		</div>
+	{/if}
+</div>
diff --git a/src/routes/post/note/+page.svelte b/src/routes/post/note/+page.svelte
index fd7dd77..dc5b152 100644
--- a/src/routes/post/note/+page.svelte
+++ b/src/routes/post/note/+page.svelte
@@ -5,6 +5,7 @@
 	import { onMount } from "svelte";
 	import { get } from "svelte/store";
 	import MarkdownEditor from "$lib/components/MarkdownEditor.svelte";
+	import SearchSelect from "$lib/components/SearchSelect.svelte";
 	import { postPath } from "$lib/paths";
 	import type { TopicDoc, UnitDoc } from "$lib/types";
 
@@ -19,6 +20,20 @@
 	let error = $state("");
 	let loading = $state(false);
 
+	const topicOptions = $derived(
+		topics.map((topic) => ({
+			value: topic._id,
+			label: topic.name,
+		})),
+	);
+	const unitOptions = $derived(
+		units.map((unit) => ({
+			value: unit._id,
+			label: `${unit.code}${unit.code2 ? ` / ${unit.code2}` : ""} — ${unit.name}`,
+			searchText: `${unit.code} ${unit.code2 ?? ""} ${unit.name}`,
+		})),
+	);
+
 	onMount(async () => {
 		await initAuth();
 		if (!get(isAuthenticated)) {
@@ -122,25 +137,25 @@
 			<div class="grid grid-cols-1 gap-6 sm:grid-cols-2">
 				<div>
 					<label for="topic" class="kicker mb-2 block">Topic (optional)</label>
-					<select id="topic" bind:value={selectedTopicId} class="field">
-						<option value="">Select a topic...</option>
-						{#each topics as topic}
-							<option value={topic._id}>{topic.name}</option>
-						{/each}
-					</select>
+					<SearchSelect
+						id="topic"
+						bind:value={selectedTopicId}
+						options={topicOptions}
+						placeholder="Select a topic..."
+						searchPlaceholder="Search topics..."
+					/>
 				</div>
 
 				<div>
 					<label for="unit" class="kicker mb-2 block">Unit</label>
 					{#if !useCustomUnit}
-						<select id="unit" bind:value={selectedUnitId} class="field">
-							<option value="">Select a unit...</option>
-							{#each units as unit}
-								<option value={unit._id}
-									>{unit.code}{unit.code2 ? ` / ${unit.code2}` : ""} — {unit.name}</option
-								>
-							{/each}
-						</select>
+						<SearchSelect
+							id="unit"
+							bind:value={selectedUnitId}
+							options={unitOptions}
+							placeholder="Select a unit..."
+							searchPlaceholder="Search units..."
+						/>
 					{/if}
 
 					<button
diff --git a/src/routes/post/question/+page.svelte b/src/routes/post/question/+page.svelte
index 16cb831..2bdeba8 100644
--- a/src/routes/post/question/+page.svelte
+++ b/src/routes/post/question/+page.svelte
@@ -5,6 +5,7 @@
 	import { onMount } from "svelte";
 	import { get } from "svelte/store";
 	import MarkdownEditor from "$lib/components/MarkdownEditor.svelte";
+	import SearchSelect from "$lib/components/SearchSelect.svelte";
 	import { postPath } from "$lib/paths";
 	import type { TopicDoc, UnitDoc } from "$lib/types";
 
@@ -19,6 +20,20 @@
 	let error = $state("");
 	let loading = $state(false);
 
+	const topicOptions = $derived(
+		topics.map((topic) => ({
+			value: topic._id,
+			label: topic.name,
+		})),
+	);
+	const unitOptions = $derived(
+		units.map((unit) => ({
+			value: unit._id,
+			label: `${unit.code}${unit.code2 ? ` / ${unit.code2}` : ""} — ${unit.name}`,
+			searchText: `${unit.code} ${unit.code2 ?? ""} ${unit.name}`,
+		})),
+	);
+
 	onMount(async () => {
 		await initAuth();
 		if (!get(isAuthenticated)) {
@@ -124,25 +139,25 @@
 			<div class="grid grid-cols-1 gap-6 sm:grid-cols-2">
 				<div>
 					<label for="topic" class="kicker mb-2 block">Topic (optional)</label>
-					<select id="topic" bind:value={selectedTopicId} class="field">
-						<option value="">Select a topic...</option>
-						{#each topics as topic}
-							<option value={topic._id}>{topic.name}</option>
-						{/each}
-					</select>
+					<SearchSelect
+						id="topic"
+						bind:value={selectedTopicId}
+						options={topicOptions}
+						placeholder="Select a topic..."
+						searchPlaceholder="Search topics..."
+					/>
 				</div>
 
 				<div>
 					<label for="unit" class="kicker mb-2 block">Unit</label>
 					{#if !useCustomUnit}
-						<select id="unit" bind:value={selectedUnitId} class="field">
-							<option value="">Select a unit...</option>
-							{#each units as unit}
-								<option value={unit._id}
-									>{unit.code}{unit.code2 ? ` / ${unit.code2}` : ""} — {unit.name}</option
-								>
-							{/each}
-						</select>
+						<SearchSelect
+							id="unit"
+							bind:value={selectedUnitId}
+							options={unitOptions}
+							placeholder="Select a unit..."
+							searchPlaceholder="Search units..."
+						/>
 					{/if}
 
 					<button