From a4a3d568dffb378af0704c3bd0ac3d5a940e8d19 Mon Sep 17 00:00:00 2001
From: liyunze <50455574+liyunze-coding@users.noreply.github.com>
Date: Wed, 2 Sep 2026 11:20:01 +0800
Subject: [PATCH] added units page and unit rail with better scrolling

---
 src/lib/components/Navbar.svelte     |  60 ++++++++++-
 src/lib/components/UnitFilter.svelte | 144 ++++++++++++++++++++++++++
 src/lib/components/UnitRail.svelte   | 119 ++++++++++++++++++++++
 src/lib/server/api.ts                |  54 ++++++++++
 src/lib/server/db.ts                 |   8 ++
 src/routes/+page.svelte              |  13 ++-
 src/routes/layout.css                |  26 ++++-
 src/routes/notes/+page.svelte        |  25 +----
 src/routes/questions/+page.svelte    |  25 +----
 src/routes/units/+page.svelte        | 146 +++++++++++++++++++++++++++
 10 files changed, 562 insertions(+), 58 deletions(-)
 create mode 100644 src/lib/components/UnitFilter.svelte
 create mode 100644 src/lib/components/UnitRail.svelte
 create mode 100644 src/routes/units/+page.svelte

diff --git a/src/lib/components/Navbar.svelte b/src/lib/components/Navbar.svelte
index 715614e..7d58d28 100644
--- a/src/lib/components/Navbar.svelte
+++ b/src/lib/components/Navbar.svelte
@@ -6,6 +6,7 @@
 	import { page } from "$app/state";
 
 	let mobileMenuOpen = $state(false);
+	let resourcesOpen = $state(false);
 	let auth = $state(false);
 	let admin = $state(false);
 	let searchQuery = $state("");
@@ -33,8 +34,10 @@
 	});
 
 	const path = $derived(page.url.pathname);
+	const onUnits = $derived(path === "/units" || path.startsWith("/units/"));
 	const onNotes = $derived(path === "/notes" || path.startsWith("/notes/"));
 	const onQuestions = $derived(path === "/questions" || path.startsWith("/questions/"));
+	const onResources = $derived(onUnits || onNotes || onQuestions);
 	const onAdmin = $derived(path === "/admin" || path.startsWith("/admin/"));
 </script>
 
@@ -43,10 +46,56 @@
 		<a href="/" class="text-ink font-serif text-[1.65rem] leading-none">Notebook</a>
 
 		<nav class="hidden items-center gap-8 md:flex">
-			<a href="/notes" class="nav-link {onNotes ? 'nav-link-active' : ''}">Notes</a>
-			<a href="/questions" class="nav-link {onQuestions ? 'nav-link-active' : ''}"
-				>Questions</a
-			>
+			<div class="relative">
+				<button
+					type="button"
+					class="nav-link relative z-20 flex items-center gap-1 {onResources
+						? 'nav-link-active'
+						: ''}"
+					aria-haspopup="true"
+					aria-expanded={resourcesOpen}
+					onclick={() => (resourcesOpen = !resourcesOpen)}
+				>
+					Resources
+					<svg
+						class="h-3 w-3 transition-transform {resourcesOpen ? '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 resourcesOpen}
+					<button
+						type="button"
+						class="fixed inset-0 z-10 cursor-default"
+						aria-label="Close menu"
+						onclick={() => (resourcesOpen = false)}
+					></button>
+					<div
+						class="border-rule bg-surface absolute top-full left-0 z-20 mt-2 w-44 rounded-sm border py-1 shadow-lg"
+					>
+						<a
+							href="/units"
+							class="nav-link block px-4 py-2 {onUnits ? 'nav-link-active' : ''}"
+							onclick={() => (resourcesOpen = false)}>Units</a
+						>
+						<a
+							href="/notes"
+							class="nav-link block px-4 py-2 {onNotes ? 'nav-link-active' : ''}"
+							onclick={() => (resourcesOpen = false)}>Notes</a
+						>
+						<a
+							href="/questions"
+							class="nav-link block px-4 py-2 {onQuestions ? 'nav-link-active' : ''}"
+							onclick={() => (resourcesOpen = false)}>Questions</a
+						>
+					</div>
+				{/if}
+			</div>
 			{#if admin}
 				<a href="/admin" class="nav-link {onAdmin ? 'nav-link-active' : ''}">Admin</a>
 			{/if}
@@ -141,6 +190,9 @@
 					class="border-rule text-ink placeholder:text-faint focus:border-primary bg-surface w-full rounded-sm border px-3 py-2 text-sm tracking-wide transition-colors outline-none"
 				/>
 			</form>
+			<a href="/units" class="nav-link block" onclick={() => (mobileMenuOpen = false)}
+				>Units</a
+			>
 			<a href="/notes" class="nav-link block" onclick={() => (mobileMenuOpen = false)}
 				>Notes</a
 			>
diff --git a/src/lib/components/UnitFilter.svelte b/src/lib/components/UnitFilter.svelte
new file mode 100644
index 0000000..9e9a161
--- /dev/null
+++ b/src/lib/components/UnitFilter.svelte
@@ -0,0 +1,144 @@
+<script lang="ts">
+	import { onMount } from "svelte";
+	import { query, mutation } from "$lib/api";
+	import { getToken, isAuthenticated, initAuth } from "$lib/stores/auth";
+	import { get } from "svelte/store";
+	import type { UnitDoc } from "$lib/types";
+
+	const MAX_PINS = 10;
+
+	let {
+		units,
+		selectedUnitId = $bindable(""),
+	}: {
+		units: UnitDoc[];
+		selectedUnitId?: string;
+	} = $props();
+
+	let pinnedIds = $state<string[]>([]);
+	let authed = $state(false);
+	let busy = $state(false);
+	let error = $state("");
+
+	onMount(async () => {
+		await initAuth();
+		if (!get(isAuthenticated)) return;
+		authed = true;
+		const token = getToken();
+		if (!token) return;
+		try {
+			pinnedIds = (await query("units:getPinned", { token })) as string[];
+		} catch {
+			// ignore
+		}
+	});
+
+	const pinnedUnits = $derived(
+		pinnedIds.map((id) => units.find((u) => u._id === id)).filter((u): u is UnitDoc => !!u),
+	);
+
+	const otherUnits = $derived(units.filter((u) => !pinnedIds.includes(u._id)));
+
+	const canPinMore = $derived(pinnedIds.length < MAX_PINS);
+
+	async function togglePin(unit: UnitDoc) {
+		const token = getToken();
+		if (!token) {
+			error = "Sign in to pin units";
+			return;
+		}
+
+		busy = true;
+		error = "";
+		try {
+			const pinned = pinnedIds.includes(unit._id);
+			pinnedIds = (await mutation(pinned ? "units:unpin" : "units:pin", {
+				token,
+				unitId: unit._id,
+			})) as string[];
+		} catch (err: any) {
+			error = err?.message ?? "Failed to update pin";
+		} finally {
+			busy = false;
+		}
+	}
+</script>
+
+{#snippet pinIcon()}
+	<svg
+		width="14"
+		height="14"
+		viewBox="0 0 24 24"
+		fill="none"
+		stroke="currentColor"
+		stroke-width="2"
+		stroke-linecap="round"
+		stroke-linejoin="round"
+		aria-hidden="true"
+	>
+		<path d="M12 17v5"></path>
+		<path
+			d="M9 10.76a2 2 0 0 1-1.11 1.79l-1.78.9A2 2 0 0 0 5 15.24V16h14v-.76a2 2 0 0 0-1.11-1.79l-1.78-.9A2 2 0 0 1 15 10.76V6h1a2 2 0 0 0 0-4H8a2 2 0 0 0 0 4h1z"
+		></path>
+	</svg>
+{/snippet}
+
+<div class="flex items-center gap-x-1 gap-y-2 overflow-x-scroll scrollbar-thin pb-2">
+	<button
+		type="button"
+		class="chip {selectedUnitId === '' ? 'chip-active' : ''}"
+		onclick={() => (selectedUnitId = "")}
+	>
+		All units
+	</button>
+
+	{#each pinnedUnits as unit (unit._id)}
+		<span class="inline-flex items-center">
+			<button
+				type="button"
+				class="chip {selectedUnitId === unit._id ? 'chip-active' : ''}"
+				onclick={() => (selectedUnitId = unit._id)}
+			>
+				{unit.code}{unit.code2 ? ` / ${unit.code2}` : ""}
+			</button>
+			<button
+				type="button"
+				class="pin-btn pin-btn-active"
+				onclick={() => togglePin(unit)}
+				disabled={busy}
+				title="Unpin unit"
+				aria-label="Unpin unit"
+			>
+				{@render pinIcon()}
+			</button>
+		</span>
+	{/each}
+
+	{#each otherUnits as unit (unit._id)}
+		<span class="inline-flex items-center">
+			<button
+				type="button"
+				class="chip {selectedUnitId === unit._id ? 'chip-active' : ''}"
+				onclick={() => (selectedUnitId = unit._id)}
+			>
+				{unit.code}{unit.code2 ? ` / ${unit.code2}` : ""}
+			</button>
+			{#if authed}
+				<button
+					type="button"
+					class="pin-btn"
+					onclick={() => togglePin(unit)}
+					disabled={busy || !canPinMore}
+					title={canPinMore ? "Pin unit" : "You can pin up to 10 units"}
+					aria-label={canPinMore ? "Pin unit" : "You can pin up to 10 units"}
+				>
+					{@render pinIcon()}
+				</button>
+			{/if}
+		</span>
+	{/each}
+
+	{#if error}
+		<span class="text-primary text-xs">{error}</span>
+	{/if}
+</div>
diff --git a/src/lib/components/UnitRail.svelte b/src/lib/components/UnitRail.svelte
new file mode 100644
index 0000000..7b097d3
--- /dev/null
+++ b/src/lib/components/UnitRail.svelte
@@ -0,0 +1,119 @@
+<script lang="ts">
+	import { onMount } from "svelte";
+	import { query, mutation } from "$lib/api";
+	import { getToken, isAuthenticated, initAuth } from "$lib/stores/auth";
+	import { get } from "svelte/store";
+	import type { UnitDoc } from "$lib/types";
+
+	const MAX_PINS = 10;
+
+	let {
+		units,
+		selectedUnitId = $bindable(""),
+	}: {
+		units: UnitDoc[];
+		selectedUnitId?: string;
+	} = $props();
+
+	let pinnedIds = $state<string[]>([]);
+	let authed = $state(false);
+	let busy = $state(false);
+	let error = $state("");
+
+	onMount(async () => {
+		await initAuth();
+		if (!get(isAuthenticated)) return;
+		authed = true;
+		const token = getToken();
+		if (!token) return;
+		try {
+			pinnedIds = (await query("units:getPinned", { token })) as string[];
+		} catch {
+			// ignore
+		}
+	});
+
+	const isPinned = (id: string) => pinnedIds.includes(id);
+	const canPinMore = $derived(pinnedIds.length < MAX_PINS);
+
+	async function togglePin(unit: UnitDoc) {
+		const token = getToken();
+		if (!token) {
+			error = "Sign in to pin units";
+			return;
+		}
+
+		busy = true;
+		error = "";
+		try {
+			const pinned = pinnedIds.includes(unit._id);
+			pinnedIds = (await mutation(pinned ? "units:unpin" : "units:pin", {
+				token,
+				unitId: unit._id,
+			})) as string[];
+		} catch (err: any) {
+			error = err?.message ?? "Failed to update pin";
+		} finally {
+			busy = false;
+		}
+	}
+</script>
+
+{#snippet pinIcon()}
+	<svg
+		width="14"
+		height="14"
+		viewBox="0 0 24 24"
+		fill="none"
+		stroke="currentColor"
+		stroke-width="2"
+		stroke-linecap="round"
+		stroke-linejoin="round"
+		aria-hidden="true"
+	>
+		<path d="M12 17v5"></path>
+		<path
+			d="M9 10.76a2 2 0 0 1-1.11 1.79l-1.78.9A2 2 0 0 0 5 15.24V16h14v-.76a2 2 0 0 0-1.11-1.79l-1.78-.9A2 2 0 0 1 15 10.76V6h1a2 2 0 0 0 0-4H8a2 2 0 0 0 0 4h1z"
+		></path>
+	</svg>
+{/snippet}
+
+<div class="unit-rail">
+	{#each units as unit (unit._id)}
+		<div class="unit-card {selectedUnitId === unit._id ? 'unit-card-active' : ''}">
+			<button
+				type="button"
+				class="flex h-full w-full flex-col items-start gap-1 text-left"
+				onclick={() => (selectedUnitId = unit._id)}
+				aria-label="Select {unit.code}"
+			>
+				<span class="text-ink font-serif text-base leading-tight"
+					>{unit.code}{unit.code2 ? ` / ${unit.code2}` : ""}</span
+				>
+				<span class="text-muted line-clamp-2 text-xs leading-snug">{unit.name}</span>
+			</button>
+			{#if authed}
+				<button
+					type="button"
+					class="pin-btn {isPinned(unit._id)
+						? 'pin-btn-active'
+						: ''} absolute top-1.5 right-1.5 z-10"
+					onclick={() => togglePin(unit)}
+					disabled={busy || (!isPinned(unit._id) && !canPinMore)}
+					title={isPinned(unit._id)
+						? "Unpin unit"
+						: canPinMore
+							? "Pin unit"
+							: "You can pin up to 10 units"}
+					aria-label={isPinned(unit._id) ? "Unpin unit" : "Pin unit"}
+				>
+					{@render pinIcon()}
+				</button>
+			{/if}
+		</div>
+	{/each}
+</div>
+
+{#if error}
+	<p class="text-primary mt-2 text-xs">{error}</p>
+{/if}
diff --git a/src/lib/server/api.ts b/src/lib/server/api.ts
index 4644098..f4741fc 100644
--- a/src/lib/server/api.ts
+++ b/src/lib/server/api.ts
@@ -283,6 +283,56 @@ function unitsCreateCustom(db: Db, args: { code: string; name: string }) {
 	return id;
 }
 
+// ---- pinned units ----
+
+const MAX_PINNED_UNITS = 10;
+
+function getPinnedUnitIds(db: Db, userId: string): string[] {
+	return (
+		db
+			.prepare("SELECT unitId FROM pinned_units WHERE userId = ? ORDER BY createdAt ASC")
+			.all(userId) as { unitId: string }[]
+	).map((row) => row.unitId);
+}
+
+function unitsGetPinned(db: Db, args: { token: string }) {
+	const user = requireAuth(db, args.token);
+	return getPinnedUnitIds(db, user._id);
+}
+
+function unitsPin(db: Db, args: { token: string; unitId: string }) {
+	const user = requireAuth(db, args.token);
+	const unit = db.prepare("SELECT id AS _id FROM units WHERE id = ?").get(args.unitId);
+	if (!unit) throw new Error("Unit not found");
+
+	const existing = db
+		.prepare("SELECT 1 AS found FROM pinned_units WHERE userId = ? AND unitId = ?")
+		.get(user._id, args.unitId);
+	if (!existing) {
+		const count = db
+			.prepare("SELECT COUNT(*) AS c FROM pinned_units WHERE userId = ?")
+			.get(user._id) as { c: number };
+		if (count.c >= MAX_PINNED_UNITS) {
+			throw new Error(`You can pin up to ${MAX_PINNED_UNITS} units`);
+		}
+		db.prepare("INSERT INTO pinned_units (userId, unitId, createdAt) VALUES (?, ?, ?)").run(
+			user._id,
+			args.unitId,
+			Date.now(),
+		);
+	}
+	return getPinnedUnitIds(db, user._id);
+}
+
+function unitsUnpin(db: Db, args: { token: string; unitId: string }) {
+	const user = requireAuth(db, args.token);
+	db.prepare("DELETE FROM pinned_units WHERE userId = ? AND unitId = ?").run(
+		user._id,
+		args.unitId,
+	);
+	return getPinnedUnitIds(db, user._id);
+}
+
 // ---- notes ----
 
 const NOTE_COLUMNS =
@@ -947,6 +997,7 @@ function adminUsersDelete(db: Db, args: { token: string; id: string }) {
 	db.exec("BEGIN");
 	try {
 		db.prepare("DELETE FROM votes WHERE userId = ?").run(args.id);
+		db.prepare("DELETE FROM pinned_units WHERE userId = ?").run(args.id);
 		for (const id of noteIds) {
 			db.prepare("DELETE FROM votes WHERE targetType = 'note' AND targetId = ?").run(id);
 			db.prepare("DELETE FROM comments WHERE parentId = ?").run(id);
@@ -1085,6 +1136,9 @@ const handlers: Record<string, Handler> = {
 	"units:getByCode": unitsGetByCode,
 	"units:getAll": unitsGetAll,
 	"units:createCustom": unitsCreateCustom,
+	"units:getPinned": unitsGetPinned,
+	"units:pin": unitsPin,
+	"units:unpin": unitsUnpin,
 	"notes:create": notesCreate,
 	"notes:list": notesList,
 	"notes:search": notesSearch,
diff --git a/src/lib/server/db.ts b/src/lib/server/db.ts
index a62706c..79c5d73 100644
--- a/src/lib/server/db.ts
+++ b/src/lib/server/db.ts
@@ -84,6 +84,13 @@ function createSchema(database: DatabaseSync) {
       value INTEGER NOT NULL
     );
 
+    CREATE TABLE IF NOT EXISTS pinned_units (
+      userId TEXT NOT NULL,
+      unitId TEXT NOT NULL,
+      createdAt INTEGER NOT NULL,
+      PRIMARY KEY (userId, unitId)
+    );
+
     CREATE TABLE IF NOT EXISTS email_verifications (
       email TEXT PRIMARY KEY,
       name TEXT NOT NULL,
@@ -102,6 +109,7 @@ function createSchema(database: DatabaseSync) {
     CREATE INDEX IF NOT EXISTS idx_comments_note ON comments(parentId);
     CREATE INDEX IF NOT EXISTS idx_comments_question ON comments(questionId);
     CREATE UNIQUE INDEX IF NOT EXISTS idx_votes_user_target ON votes(userId, targetType, targetId);
+    CREATE INDEX IF NOT EXISTS idx_pinned_units_user ON pinned_units(userId);
   `);
 }
 
diff --git a/src/routes/+page.svelte b/src/routes/+page.svelte
index a21700f..476db1a 100644
--- a/src/routes/+page.svelte
+++ b/src/routes/+page.svelte
@@ -47,16 +47,15 @@
 		{:else if error}
 			<p class="kicker">{error}</p>
 		{:else}
-			<div class="grid grid-cols-1 sm:grid-cols-2 sm:gap-x-5">
+			<div class="unit-rail">
 				{#each units as unit}
-					<a
-						href="/units/{unit.code}"
-						class="group border-rule flex items-baseline justify-between gap-4 border-b py-3"
-					>
-						<span class="text-ink group-hover:text-primary font-serif text-lg"
+					<a href="/units/{unit.code}" class="unit-card group flex flex-col gap-1">
+						<span
+							class="text-ink group-hover:text-primary font-serif text-base leading-tight"
 							>{unit.code}{unit.code2 ? ` / ${unit.code2}` : ""}</span
 						>
-						<span class="text-muted truncate text-sm">{unit.name}</span>
+						<span class="text-muted line-clamp-2 text-xs leading-snug">{unit.name}</span
+						>
 					</a>
 				{/each}
 			</div>
diff --git a/src/routes/layout.css b/src/routes/layout.css
index c40835d..b5ad631 100644
--- a/src/routes/layout.css
+++ b/src/routes/layout.css
@@ -105,7 +105,7 @@ button {
 }
 
 .chip {
-	@apply border-rule text-ink hover:border-ink bg-surface inline-flex items-center rounded-sm border px-3 py-1.5 font-sans text-[11px] font-medium tracking-[0.12em] uppercase transition-colors;
+	@apply border-rule whitespace-nowrap text-ink hover:border-ink bg-surface inline-flex items-center rounded-sm border px-3 py-1.5 font-sans text-[11px] font-medium tracking-[0.12em] uppercase transition-colors;
 }
 
 .chip-active {
@@ -124,6 +124,30 @@ button {
 	@apply text-ink hover:border-primary hover:text-primary bg-surface inline-flex h-8 min-w-8 items-center justify-center rounded-sm border border-transparent px-1.5 font-sans text-xs font-medium transition-colors;
 }
 
+.pin-btn {
+	@apply text-faint hover:text-ink ml-1 inline-flex h-7 w-7 items-center justify-center rounded-sm border border-transparent transition-colors disabled:cursor-not-allowed disabled:opacity-50;
+}
+
+.pin-btn-active {
+	@apply text-primary hover:text-primary-dark;
+}
+
+.unit-rail {
+	@apply flex gap-3 overflow-x-scroll py-1 scrollbar-thin pb-2;
+}
+
+.unit-rail::-webkit-scrollbar {
+	display: none;
+}
+
+.unit-card {
+	@apply border-rule bg-surface hover:border-ink relative w-44 shrink-0 rounded-sm border p-3 transition-colors;
+}
+
+.unit-card-active {
+	@apply border-primary hover:border-primary;
+}
+
 .thread-branch {
 	@apply border-rule hover:border-secondary w-3 shrink-0 cursor-pointer self-stretch border-l-2 transition hover:brightness-150;
 }
diff --git a/src/routes/notes/+page.svelte b/src/routes/notes/+page.svelte
index d7e0a0f..5986611 100644
--- a/src/routes/notes/+page.svelte
+++ b/src/routes/notes/+page.svelte
@@ -2,6 +2,7 @@
 	import { query } from "$lib/api";
 	import { onMount } from "svelte";
 	import FeedRow from "$lib/components/FeedRow.svelte";
+	import UnitFilter from "$lib/components/UnitFilter.svelte";
 	import { timeAgo } from "$lib/time";
 	import type { NoteDoc, UnitDoc } from "$lib/types";
 
@@ -20,11 +21,6 @@
 		loading = false;
 	});
 
-	const usedUnits = $derived.by(() => {
-		const ids = new Set(notes.map((n) => n.unitId));
-		return units.filter((u) => ids.has(u._id));
-	});
-
 	const visible = $derived.by(() => {
 		const q = searchQuery.trim().toLowerCase();
 		let list = selectedUnitId ? notes.filter((n) => n.unitId === selectedUnitId) : notes;
@@ -59,24 +55,7 @@
 	</div>
 
 	<div class="border-rule flex flex-wrap items-center justify-between gap-4 border-b py-4">
-		<div class="flex flex-wrap gap-2">
-			<button
-				type="button"
-				class="chip {selectedUnitId === '' ? 'chip-active' : ''}"
-				onclick={() => (selectedUnitId = "")}
-			>
-				All units
-			</button>
-			{#each usedUnits as unit}
-				<button
-					type="button"
-					class="chip {selectedUnitId === unit._id ? 'chip-active' : ''}"
-					onclick={() => (selectedUnitId = unit._id)}
-				>
-					{unit.code}{unit.code2 ? ` / ${unit.code2}` : ""}
-				</button>
-			{/each}
-		</div>
+		<UnitFilter bind:selectedUnitId {units} />
 		<div class="flex gap-4">
 			<button
 				type="button"
diff --git a/src/routes/questions/+page.svelte b/src/routes/questions/+page.svelte
index 6914c3d..2df85ef 100644
--- a/src/routes/questions/+page.svelte
+++ b/src/routes/questions/+page.svelte
@@ -2,6 +2,7 @@
 	import { query } from "$lib/api";
 	import { onMount } from "svelte";
 	import FeedRow from "$lib/components/FeedRow.svelte";
+	import UnitFilter from "$lib/components/UnitFilter.svelte";
 	import { timeAgo } from "$lib/time";
 	import type { QuestionDoc, UnitDoc } from "$lib/types";
 
@@ -23,11 +24,6 @@
 		loading = false;
 	});
 
-	const usedUnits = $derived.by(() => {
-		const ids = new Set(questions.map((q) => q.unitId));
-		return units.filter((u) => ids.has(u._id));
-	});
-
 	const visible = $derived.by(() => {
 		const q = searchQuery.trim().toLowerCase();
 		let list = selectedUnitId
@@ -66,24 +62,7 @@
 	</div>
 
 	<div class="border-rule flex flex-wrap items-center justify-between gap-4 border-b py-4">
-		<div class="flex flex-wrap gap-2">
-			<button
-				type="button"
-				class="chip {selectedUnitId === '' ? 'chip-active' : ''}"
-				onclick={() => (selectedUnitId = "")}
-			>
-				All units
-			</button>
-			{#each usedUnits as unit}
-				<button
-					type="button"
-					class="chip {selectedUnitId === unit._id ? 'chip-active' : ''}"
-					onclick={() => (selectedUnitId = unit._id)}
-				>
-					{unit.code}{unit.code2 ? ` / ${unit.code2}` : ""}
-				</button>
-			{/each}
-		</div>
+		<UnitFilter bind:selectedUnitId {units} />
 		<div class="flex gap-4">
 			<button
 				type="button"
diff --git a/src/routes/units/+page.svelte b/src/routes/units/+page.svelte
new file mode 100644
index 0000000..3fd23b6
--- /dev/null
+++ b/src/routes/units/+page.svelte
@@ -0,0 +1,146 @@
+<script lang="ts">
+	import { query } from "$lib/api";
+	import { onMount } from "svelte";
+	import FeedRow from "$lib/components/FeedRow.svelte";
+	import UnitRail from "$lib/components/UnitRail.svelte";
+	import { timeAgo } from "$lib/time";
+	import type { NoteDoc, QuestionDoc, UnitDoc } from "$lib/types";
+
+	let units: UnitDoc[] = $state([]);
+	let notes: NoteDoc[] = $state([]);
+	let questions: QuestionDoc[] = $state([]);
+	let loading = $state(true);
+	let contentLoading = $state(false);
+	let selectedUnitId = $state("");
+
+	const selectedUnit = $derived(units.find((u) => u._id === selectedUnitId) ?? null);
+
+	onMount(async () => {
+		try {
+			units = (await query("units:getAll")) as UnitDoc[];
+			selectedUnitId = units[0]?._id ?? "";
+		} finally {
+			loading = false;
+		}
+	});
+
+	$effect(() => {
+		loadContent(selectedUnitId);
+	});
+
+	async function loadContent(id: string) {
+		if (!id) {
+			notes = [];
+			questions = [];
+			return;
+		}
+		contentLoading = true;
+		try {
+			const [n, q] = await Promise.all([
+				query("notes:list", { unitId: id }),
+				query("questions:list", { unitId: id }),
+			]);
+			notes = n as NoteDoc[];
+			questions = q as QuestionDoc[];
+		} finally {
+			contentLoading = false;
+		}
+	}
+</script>
+
+<svelte:head>
+	<title>Units — Notebook</title>
+</svelte:head>
+
+<div class="page">
+	<div class="border-rule border-b pb-6">
+		<h1 class="text-ink font-serif text-4xl font-medium">Units</h1>
+		<p class="text-muted mt-2 text-sm">
+			Browse notes and questions by unit. Pin the units you are studying to keep them handy.
+		</p>
+	</div>
+
+	{#if loading}
+		<p class="kicker py-16">Loading</p>
+	{:else}
+		<div class="border-rule border-b py-5">
+			<UnitRail {units} bind:selectedUnitId />
+		</div>
+
+		{#if selectedUnit}
+			<div class="pt-6">
+				<div class="flex flex-wrap items-baseline justify-between gap-x-4 gap-y-1">
+					<h2 class="text-ink font-serif text-2xl font-medium">
+						{selectedUnit.code}{selectedUnit.code2 ? ` / ${selectedUnit.code2}` : ""}
+					</h2>
+					<p class="text-muted text-sm">{selectedUnit.name}</p>
+				</div>
+				{#if selectedUnit.description}
+					<p class="text-muted mt-1 text-sm">{selectedUnit.description}</p>
+				{/if}
+
+				{#if contentLoading}
+					<p class="kicker py-16">Loading</p>
+				{:else}
+					{#if notes.length > 0}
+						<p class="kicker border-rule mt-8 border-t pt-8">Notes</p>
+						{#each notes as note}
+							<FeedRow
+								href="/notes/{note._id}"
+								title={note.title}
+								unitCode={selectedUnit.code +
+									(selectedUnit.code2 ? ` / ${selectedUnit.code2}` : "")}
+								meta="{note.authorName} · {timeAgo(
+									note.createdAt,
+								)} · {note.commentCount} comment{note.commentCount === 1
+									? ''
+									: 's'}"
+								voteCount={note.voteCount}
+								targetType="note"
+								targetId={note._id}
+							/>
+						{/each}
+					{/if}
+
+					{#if questions.length > 0}
+						<p class="kicker border-rule mt-8 border-t pt-8">Questions</p>
+						{#each questions as question}
+							<FeedRow
+								href="/questions/{question._id}"
+								title={question.title}
+								unitCode={selectedUnit.code +
+									(selectedUnit.code2 ? ` / ${selectedUnit.code2}` : "")}
+								meta="{question.authorName} · {timeAgo(
+									question.createdAt,
+								)} · {question.answerCount} answer{question.answerCount === 1
+									? ''
+									: 's'}"
+								voteCount={question.voteCount}
+								targetType="question"
+								targetId={question._id}
+							/>
+						{/each}
+					{/if}
+
+					{#if notes.length === 0 && questions.length === 0}
+						<p class="text-muted mt-8 text-sm">No content for this unit yet.</p>
+						<div class="mt-4 flex gap-4">
+							<a
+								href="/post/note"
+								class="text-secondary hover:text-secondary-dark text-sm"
+								>Post a note</a
+							>
+							<a
+								href="/post/question"
+								class="text-secondary hover:text-secondary-dark text-sm"
+								>Ask a question</a
+							>
+						</div>
+					{/if}
+				{/if}
+			</div>
+		{:else}
+			<p class="text-muted py-16 text-sm">Select a unit to see its notes and questions.</p>
+		{/if}
+	{/if}
+</div>