diff --git a/web/src/app.css b/web/src/app.css
index c3e72ae..90737c7 100644
--- a/web/src/app.css
+++ b/web/src/app.css
@@ -160,6 +160,19 @@ button:disabled {
 	border-radius: var(--radius-m);
 }
 
+.control {
+	padding: var(--space-1) var(--space-2);
+	border: 1px solid var(--border);
+	border-radius: var(--radius-s);
+	background: var(--surface);
+	max-width: var(--control-max-width);
+}
+
+input.control[type='number'] {
+	font-family: var(--font-mono);
+	width: 100%;
+}
+
 .error-banner {
 	padding: var(--space-2) var(--space-3);
 	border: 1px solid var(--danger);
diff --git a/web/src/lib/components/ui/Button.svelte b/web/src/lib/components/ui/Button.svelte
new file mode 100644
index 0000000..72e7b68
--- /dev/null
+++ b/web/src/lib/components/ui/Button.svelte
@@ -0,0 +1,77 @@
+<script lang="ts">
+	import type { Snippet } from 'svelte';
+
+	interface Props {
+		variant?: 'primary' | 'secondary';
+		type?: 'button' | 'submit';
+		disabled?: boolean;
+		busy?: boolean;
+		busyText?: string;
+		onclick?: () => void;
+		children: Snippet;
+	}
+
+	let {
+		variant = 'primary',
+		type = 'button',
+		disabled = false,
+		busy = false,
+		busyText = '',
+		onclick,
+		children
+	}: Props = $props();
+</script>
+
+<button
+	{type}
+	class={variant}
+	aria-busy={busy}
+	disabled={disabled || busy}
+	onclick={onclick}
+>
+	{#if busy && busyText}
+		{busyText}
+	{:else}
+		{@render children()}
+	{/if}
+</button>
+
+<style>
+	button {
+		padding: var(--space-2) var(--space-3);
+		border-radius: var(--radius-s);
+		border: 1px solid transparent;
+		font-weight: 600;
+		font-size: var(--text-m);
+		cursor: pointer;
+		transition:
+			background var(--transition-fast),
+			border-color var(--transition-fast),
+			color var(--transition-fast);
+	}
+
+	button.primary {
+		background: var(--accent);
+		color: var(--accent-contrast);
+	}
+
+	button.primary:hover:not(:disabled) {
+		background: var(--accent-hover);
+	}
+
+	button.secondary {
+		background: var(--surface);
+		color: var(--text);
+		border-color: var(--border);
+	}
+
+	button.secondary:hover:not(:disabled) {
+		border-color: var(--accent);
+		color: var(--accent);
+	}
+
+	button:disabled {
+		opacity: 0.55;
+		cursor: not-allowed;
+	}
+</style>
diff --git a/web/src/lib/components/ui/CheckboxField.svelte b/web/src/lib/components/ui/CheckboxField.svelte
new file mode 100644
index 0000000..745532b
--- /dev/null
+++ b/web/src/lib/components/ui/CheckboxField.svelte
@@ -0,0 +1,42 @@
+<script lang="ts">
+	interface Props {
+		id: string;
+		label: string;
+		checked?: boolean;
+		hint?: string;
+	}
+
+	let { id, label, checked = $bindable(false), hint }: Props = $props();
+</script>
+
+<div class="checkbox">
+	<input id={id} type="checkbox" bind:checked />
+	<label for={id}>{label}</label>
+</div>
+{#if hint}
+	<p class="hint text-caption text-muted">{hint}</p>
+{/if}
+
+<style>
+	.checkbox {
+		display: flex;
+		align-items: center;
+		gap: var(--space-2);
+		margin-bottom: var(--space-3);
+	}
+
+	input[type='checkbox'] {
+		width: 1rem;
+		height: 1rem;
+		cursor: pointer;
+	}
+
+	label {
+		font-size: var(--text-m);
+		cursor: pointer;
+	}
+
+	.hint {
+		margin: calc(-1 * var(--space-3)) 0 var(--space-3);
+	}
+</style>
diff --git a/web/src/lib/components/ui/ColorField.svelte b/web/src/lib/components/ui/ColorField.svelte
new file mode 100644
index 0000000..3c94e03
--- /dev/null
+++ b/web/src/lib/components/ui/ColorField.svelte
@@ -0,0 +1,25 @@
+<script lang="ts">
+	import Field from './Field.svelte';
+
+	interface Props {
+		id: string;
+		label: string;
+		value?: string;
+		hint?: string;
+	}
+
+	let { id, label, value = $bindable('#000000'), hint }: Props = $props();
+</script>
+
+<Field {id} {label} {hint}>
+	<input id={id} class="control swatch" type="color" bind:value />
+</Field>
+
+<style>
+	.swatch {
+		height: var(--control-height);
+		width: 3.5rem;
+		padding: 2px;
+		cursor: pointer;
+	}
+</style>
diff --git a/web/src/lib/components/ui/EmptyState.svelte b/web/src/lib/components/ui/EmptyState.svelte
new file mode 100644
index 0000000..cba7241
--- /dev/null
+++ b/web/src/lib/components/ui/EmptyState.svelte
@@ -0,0 +1,38 @@
+<script lang="ts">
+	import type { Snippet } from 'svelte';
+
+	interface Props {
+		title: string;
+		hint?: string;
+		children?: Snippet;
+	}
+
+	let { title, hint, children }: Props = $props();
+</script>
+
+<div class="empty panel">
+	<p class="title">{title}</p>
+	{#if hint}
+		<p class="text-caption text-muted">{hint}</p>
+	{/if}
+	{#if children}
+		{@render children()}
+	{/if}
+</div>
+
+<style>
+	.empty {
+		display: flex;
+		flex-direction: column;
+		align-items: center;
+		justify-content: center;
+		gap: var(--space-1);
+		min-height: 8rem;
+		padding: var(--space-4);
+		text-align: center;
+	}
+
+	.title {
+		font-weight: 600;
+	}
+</style>
diff --git a/web/src/lib/components/ui/Field.svelte b/web/src/lib/components/ui/Field.svelte
new file mode 100644
index 0000000..a64df98
--- /dev/null
+++ b/web/src/lib/components/ui/Field.svelte
@@ -0,0 +1,29 @@
+<script lang="ts">
+	import type { Snippet } from 'svelte';
+
+	interface Props {
+		id: string;
+		label: string;
+		hint?: string;
+		children: Snippet;
+	}
+
+	let { id, label, hint, children }: Props = $props();
+</script>
+
+<div class="field">
+	<label class="text-caption text-muted" for={id}>{label}</label>
+	{@render children()}
+	{#if hint}
+		<p class="hint text-caption text-muted">{hint}</p>
+	{/if}
+</div>
+
+<style>
+	.field {
+		display: flex;
+		flex-direction: column;
+		gap: var(--space-1);
+		margin-bottom: var(--space-3);
+	}
+</style>
diff --git a/web/src/lib/components/ui/SelectField.svelte b/web/src/lib/components/ui/SelectField.svelte
new file mode 100644
index 0000000..493dcb9
--- /dev/null
+++ b/web/src/lib/components/ui/SelectField.svelte
@@ -0,0 +1,21 @@
+<script lang="ts">
+	import Field from './Field.svelte';
+
+	interface Props {
+		id: string;
+		label: string;
+		value?: string;
+		options: { value: string; label: string }[];
+		hint?: string;
+	}
+
+	let { id, label, value = $bindable(''), options, hint }: Props = $props();
+</script>
+
+<Field {id} {label} {hint}>
+	<select id={id} class="control" bind:value>
+		{#each options as option (option.value)}
+			<option value={option.value}>{option.label}</option>
+		{/each}
+	</select>
+</Field>
diff --git a/web/src/lib/components/ui/SliderField.svelte b/web/src/lib/components/ui/SliderField.svelte
new file mode 100644
index 0000000..9b14b02
--- /dev/null
+++ b/web/src/lib/components/ui/SliderField.svelte
@@ -0,0 +1,43 @@
+<script lang="ts">
+	import Field from './Field.svelte';
+
+	interface Props {
+		id: string;
+		label: string;
+		value?: number;
+		min?: number;
+		max?: number;
+		step?: number;
+		hint?: string;
+	}
+
+	let { id, label, value = $bindable(0), min, max, step, hint }: Props = $props();
+</script>
+
+<Field {id} {label} {hint}>
+	<div class="row">
+		<input id={id} type="range" min={min} max={max} step={step} bind:value />
+		<output>{value}</output>
+	</div>
+</Field>
+
+<style>
+	.row {
+		display: flex;
+		align-items: center;
+		gap: var(--space-2);
+		max-width: var(--control-max-width);
+	}
+
+	input[type='range'] {
+		flex: 1;
+		accent-color: var(--accent);
+	}
+
+	output {
+		min-width: 3ch;
+		text-align: right;
+		font-family: var(--font-mono);
+		font-size: var(--text-s);
+	}
+</style>
diff --git a/web/src/lib/components/ui/TextField.svelte b/web/src/lib/components/ui/TextField.svelte
new file mode 100644
index 0000000..2a290de
--- /dev/null
+++ b/web/src/lib/components/ui/TextField.svelte
@@ -0,0 +1,20 @@
+<script lang="ts">
+	import Field from './Field.svelte';
+
+	interface Props {
+		id: string;
+		label: string;
+		value?: string | number;
+		type?: 'number' | 'text';
+		min?: number;
+		max?: number;
+		step?: number;
+		hint?: string;
+	}
+
+	let { id, label, value = $bindable(''), type = 'text', min, max, step, hint }: Props = $props();
+</script>
+
+<Field {id} {label} {hint}>
+	<input class="control" {id} {type} min={min} max={max} step={step} bind:value />
+</Field>