diff --git a/.gitignore b/.gitignore
index 5a4e6ecc..720eb26b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -28,13 +28,11 @@ assets/css/routes/docs/*
 #   cd assets/admin && npm ci && npm run build
 #   cd assets/creator-studio && npm ci && npm run build
 /assets/admin/node_modules/
-/assets/admin/build/*
-!/assets/admin/build/.gitkeep
+/assets/admin/build/
 assets/admin/.vite-temp/
 
 /assets/creator-studio/node_modules/
-/assets/creator-studio/build/*
-!/assets/creator-studio/build/.gitkeep
+/assets/creator-studio/build/
 
 # PHP installed dependencies
 /vendor/*
diff --git a/assets/creator-studio/build/.gitkeep b/assets/creator-studio/build/.gitkeep
deleted file mode 100644
index e69de29b..00000000
diff --git a/assets/creator-studio/src/components/category-select.tsx b/assets/creator-studio/src/components/category-select.tsx
index 47690b5c..8cebc69b 100644
--- a/assets/creator-studio/src/components/category-select.tsx
+++ b/assets/creator-studio/src/components/category-select.tsx
@@ -13,7 +13,7 @@ import { __, sprintf } from '@wordpress/i18n';
 
 import { useAnchoredPanel } from '../hooks/use-anchored-panel';
 
-export type CategoryOption = { id: number; name: string };
+export type CategoryOption = { id: number; name: string; depth?: number; path?: string };
 
 type Props = {
 	options: CategoryOption[];
@@ -42,7 +42,8 @@ export function CategorySelect({ options, value, onChange }: Props) {
 		if (keyword === '') {
 			return options;
 		}
-		return options.filter((option) => option.name.toLowerCase().includes(keyword));
+		// 同时匹配完整路径：搜上级分类名也能把它的子分类带出来。
+		return options.filter((option) => (option.path || option.name).toLowerCase().includes(keyword));
 	}, [options, query]);
 
 	// 每次打开都从干净的搜索词开始，避免上次的过滤条件把列表藏起来。
@@ -87,6 +88,8 @@ export function CategorySelect({ options, value, onChange }: Props) {
 								<label
 									key={option.id}
 									className={`jio-creator-picker__item${active ? ' is-active' : ''}`}
+									style={{ paddingLeft: `${10 + (option.depth || 0) * 16}px` }}
+									title={option.path || option.name}
 								>
 									<input type="checkbox" checked={active} onChange={() => toggle(option.id)} />
 									<span className="jio-creator-picker__name">{option.name}</span>
@@ -134,7 +137,9 @@ export function CategorySelect({ options, value, onChange }: Props) {
 					) : (
 						chosen.map((option) => (
 							<span key={option.id} className="jio-creator-select__token">
-								<span className="jio-creator-select__token-label">{option.name}</span>
+								<span className="jio-creator-select__token-label" title={option.path || option.name}>
+									{option.name}
+								</span>
 								<button
 									type="button"
 									className="jio-creator-select__token-x"
diff --git a/assets/creator-studio/src/components/tool-menu.tsx b/assets/creator-studio/src/components/tool-menu.tsx
index 989595f0..173be68b 100644
--- a/assets/creator-studio/src/components/tool-menu.tsx
+++ b/assets/creator-studio/src/components/tool-menu.tsx
@@ -130,8 +130,11 @@ export function ToolMenu({
 				aria-expanded={open ? 'true' : 'false'}
 			>
 				<i className={icon} aria-hidden="true" />
-				<span className="jio-creator__tool-label">{label}</span>
-				<i className="fa fas fa-caret-down jio-creator__tool-caret" aria-hidden="true" />
+				{/* 下三角与文字同一行参与排版：按钮再窄也只会压缩文字，不会压到三角上。 */}
+				<span className="jio-creator__tool-meta">
+					<span className="jio-creator__tool-label">{label}</span>
+					<i className="fa fas fa-caret-down jio-creator__tool-caret" aria-hidden="true" />
+				</span>
 			</button>
 			{menu}
 		</div>
diff --git a/assets/creator-studio/src/styles/studio.scss b/assets/creator-studio/src/styles/studio.scss
index c22774d0..55da60c6 100644
--- a/assets/creator-studio/src/styles/studio.scss
+++ b/assets/creator-studio/src/styles/studio.scss
@@ -283,11 +283,19 @@ body.jio-page-submit.has-static-nav {
 	white-space: nowrap;
 }
 
-/* 下拉触发器右下角的小三角：告诉作者这里还有更多选项。 */
-.jio-creator__tool-caret {
-	position: absolute;
-	right: 3px;
-	bottom: 4px;
+/* 文字 + 下三角同处一行：三角参与排版，不会再被绝对定位盖到文字上。 */
+.jio-creator__tool-meta {
+	display: inline-flex;
+	max-width: 100%;
+	align-items: center;
+	justify-content: center;
+	gap: 2px;
+	min-width: 0;
+}
+
+/* 三角要压过 `.jio-creator__tool-btn i` 的图标字号，所以带上按钮前缀。 */
+.jio-creator__tool-btn .jio-creator__tool-caret {
+	flex: 0 0 auto;
 	color: #b0b9b6;
 	font-size: 8px;
 	line-height: 1;
@@ -857,6 +865,10 @@ body.jio-page-submit.has-static-nav {
 		font-size: 10px;
 	}
 
+	.jio-creator__tool-meta {
+		gap: 1px;
+	}
+
 	.jio-creator__canvas {
 		width: calc(100% - 20px);
 		margin: 14px auto 0;
diff --git a/src/Core/CreatorRest.php b/src/Core/CreatorRest.php
index d3b965fe..637adab0 100644
--- a/src/Core/CreatorRest.php
+++ b/src/Core/CreatorRest.php
@@ -127,7 +127,7 @@ final class CreatorRest {
 			? (array) get_post_meta($source->ID, DomainModel::POST_META_KEY, true)
 			: [];
 
-		$terms  = $this->term_payload($settings, $source, $snapshot);
+		$terms = $this->term_payload($settings, $source, $snapshot);
 		$viewer = $user_id > 0 ? get_userdata($user_id) : null;
 		$ident  = $this->identity_payload($viewer instanceof \WP_User ? $viewer : null);
 
@@ -551,21 +551,15 @@ final class CreatorRest {
 	 * @return array<string, mixed>
 	 */
 	private function term_payload(array $settings, ?\WP_Post $source, array $snapshot): array {
-		$cat_args = [
-			'taxonomy'   => 'category',
-			'hide_empty' => false,
-			'orderby'    => 'name',
-			'order'      => 'ASC',
-		];
-		if (!empty($settings['allowed_cat_ids'])) {
-			$cat_args['include'] = $settings['allowed_cat_ids'];
-		} else {
-			$cat_args['parent'] = 0;
-		}
-		$terms = get_terms($cat_args);
+		// 分类树按层级深度优先展平，二级 / 三级分类不会因为 parent=0 过滤而消失。
 		$categories = [];
-		foreach (is_array($terms) ? $terms : [] as $term) {
-			$categories[] = ['id' => (int) $term->term_id, 'name' => (string) $term->name];
+		foreach (SubmitCategories::tree($settings) as $node) {
+			$categories[] = [
+				'id'    => (int) $node['term']->term_id,
+				'name'  => (string) $node['term']->name,
+				'depth' => (int) $node['depth'],
+				'path'  => (string) $node['path'],
+			];
 		}
 
 		$current = $source instanceof \WP_Post && $snapshot === []
diff --git a/src/Core/FrontSubmitSave.php b/src/Core/FrontSubmitSave.php
index 25443e55..9f7a91b2 100644
--- a/src/Core/FrontSubmitSave.php
+++ b/src/Core/FrontSubmitSave.php
@@ -103,10 +103,9 @@ trait FrontSubmitSave {
             }
         }
 
-        // Allowed category whitelist.
-        $allowed = $settings['allowed_cat_ids'] ?? [];
-        if (!empty($allowed) && !empty($categories)) {
-            $categories = array_values(array_intersect($categories, $allowed));
+        // Allowed category whitelist: 选中上级分类时，其全部子分类同样可选。
+        if (!empty($categories)) {
+            $categories = SubmitCategories::filter_ids($categories, $settings);
             if (!$is_draft && empty($categories)) {
                 return ['success' => false, 'message' => __('所选分类不可用', 'jio')];
             }
diff --git a/src/Core/SubmissionVersion.php b/src/Core/SubmissionVersion.php
index 0d4b91e0..5b6c1b98 100644
--- a/src/Core/SubmissionVersion.php
+++ b/src/Core/SubmissionVersion.php
@@ -427,9 +427,8 @@ final class SubmissionVersion {
 
 		if (isset($snapshot['categories']) && is_array($snapshot['categories'])) {
 			$cats = array_values(array_unique(array_filter(array_map('absint', $snapshot['categories']))));
-			$allowed = is_array($settings['allowed_cat_ids'] ?? null) ? array_map('intval', $settings['allowed_cat_ids']) : [];
-			if ($allowed !== [] && $cats !== []) {
-				$cats = array_values(array_intersect($cats, $allowed));
+			if ($cats !== []) {
+				$cats = SubmitCategories::filter_ids($cats, $settings);
 			}
 			wp_set_post_categories($post_id, $cats);
 		}
diff --git a/src/Core/SubmitCategories.php b/src/Core/SubmitCategories.php
new file mode 100644
index 00000000..530eda4a
--- /dev/null
+++ b/src/Core/SubmitCategories.php
@@ -0,0 +1,197 @@
+<?php
+/**
+ * 投稿可选分类的解析。
+ *
+ * 前台投稿的分类白名单（「投稿允许选择的分类」）按"选了上级就包含其全部子级"
+ * 的语义生效：白名单里出现某个分类时，它的所有后代分类都可选；白名单为空时
+ * 全部分类可选。列表本身始终是完整的层级树，而不是只有顶级分类——否则二级、
+ * 三级分类会从投稿页里彻底消失。
+ *
+ * 创作者工作台（CreatorRest）与经典投稿表单（templates/parts/submit）共用这里
+ * 的结果，避免两处各自拼一套查询。
+ *
+ * @package Jio
+ */
+
+namespace Jio\Core;
+
+defined('ABSPATH') || exit;
+
+final class SubmitCategories {
+
+	/**
+	 * 请求内缓存：一次投稿页渲染 / 一次 REST 请求只查一次分类表。
+	 *
+	 * @var array<string, array{terms: \WP_Term[], tree: array<int, array{term: \WP_Term, depth: int, path: string}>, ids: array<int, true>}>
+	 */
+	private static array $cache = [];
+
+	/**
+	 * 可选的分类树，按层级深度优先展平。
+	 *
+	 * 每个元素都带 `depth`（顶级为 0）与 `path`（从顶级到自身的名称串），
+	 * 前端可以按需缩进或显示完整路径。
+	 *
+	 * @param array<string, mixed> $settings 投稿设置（读取 allowed_cat_ids）。
+	 * @return array<int, array{term: \WP_Term, depth: int, path: string}>
+	 */
+	public static function tree(array $settings): array {
+		return self::resolve($settings)['tree'];
+	}
+
+	/**
+	 * 一次解析出「可选分类树」与「允许的分类 ID 集合」。
+	 *
+	 * @param array<string, mixed> $settings
+	 * @return array{terms: \WP_Term[], tree: array<int, array{term: \WP_Term, depth: int, path: string}>, ids: array<int, true>}
+	 */
+	private static function resolve(array $settings): array {
+		$signature = self::signature($settings);
+		if (isset(self::$cache[$signature])) {
+			return self::$cache[$signature];
+		}
+
+		$whitelist = self::whitelist($settings);
+		// 白名单为空 = 全部分类可选，此时不做 ID 过滤，避免多一次全表查询，
+		// 也避免分类查询异常时把正常投稿误判成"所选分类不可用"。
+		$allowed = $whitelist === [] ? null : self::expand_whitelist($whitelist);
+
+		$args = [
+			'taxonomy'   => 'category',
+			'hide_empty' => false,
+			'orderby'    => 'name',
+			'order'      => 'ASC',
+			'number'     => 0,
+		];
+		if ($allowed !== null) {
+			// include 只收窄查询范围，父子关系仍由 flatten() 复原。
+			$args['include'] = array_keys($allowed);
+		}
+
+		$terms = get_terms($args);
+		$terms = is_array($terms) ? $terms : [];
+		if ($allowed !== null) {
+			$terms = array_values(array_filter(
+				$terms,
+				static fn($term): bool => isset($allowed[(int) $term->term_id])
+			));
+		}
+
+		$ids = [];
+		foreach ($terms as $term) {
+			$ids[(int) $term->term_id] = true;
+		}
+
+		self::$cache[$signature] = [
+			'terms' => $terms,
+			'tree'  => self::flatten($terms),
+			'ids'   => $ids,
+		];
+
+		return self::$cache[$signature];
+	}
+
+	/**
+	 * 过滤提交上来的分类 ID，只保留允许的部分。
+	 *
+	 * 白名单未启用时原样返回（不查分类表），启用时按"含后代"的集合过滤。
+	 *
+	 * @param int[]                $ids
+	 * @param array<string, mixed> $settings
+	 * @return int[]
+	 */
+	public static function filter_ids(array $ids, array $settings): array {
+		$whitelist = self::whitelist($settings);
+		if ($whitelist === []) {
+			return array_values(array_unique(array_filter(array_map('intval', $ids))));
+		}
+		$allowed = self::expand_whitelist($whitelist);
+		$kept = [];
+		foreach ($ids as $id) {
+			$id = (int) $id;
+			if ($id > 0 && isset($allowed[$id])) {
+				$kept[] = $id;
+			}
+		}
+		return array_values(array_unique($kept));
+	}
+
+	/**
+	 * 展开白名单：选中分类 + 其全部后代。
+	 *
+	 * @param int[] $whitelist
+	 * @return array<int, true>
+	 */
+	private static function expand_whitelist(array $whitelist): array {
+		$ids = [];
+		foreach ($whitelist as $id) {
+			$ids[$id] = true;
+			$children = get_term_children($id, 'category');
+			foreach (is_array($children) ? $children : [] as $child) {
+				$ids[(int) $child] = true;
+			}
+		}
+		return $ids;
+	}
+
+	/**
+	 * 配置里显式选中的分类（未展开后代）。
+	 *
+	 * @param array<string, mixed> $settings
+	 * @return int[]
+	 */
+	private static function whitelist(array $settings): array {
+		if (!is_array($settings['allowed_cat_ids'] ?? null)) {
+			return [];
+		}
+		return array_values(array_filter(array_map('intval', $settings['allowed_cat_ids'])));
+	}
+
+	/**
+	 * 把分类按父子关系整理成深度优先序列。
+	 *
+	 * 父级不在集合里（例如只授权了某个子分类）的分类直接作为根节点，
+	 * 不会被静默丢弃。
+	 *
+	 * @param \WP_Term[] $terms
+	 * @return array<int, array{term: \WP_Term, depth: int, path: string}>
+	 */
+	private static function flatten(array $terms): array {
+		$by_parent = [];
+		$present = [];
+		foreach ($terms as $term) {
+			$present[(int) $term->term_id] = true;
+		}
+		foreach ($terms as $term) {
+			$parent = (int) $term->parent;
+			if (!isset($present[$parent])) {
+				$parent = 0;
+			}
+			$by_parent[$parent][] = $term;
+		}
+
+		$out = [];
+		$walk = static function (int $parent, int $depth, string $prefix) use (&$walk, $by_parent, &$out): void {
+			foreach ($by_parent[$parent] ?? [] as $term) {
+				$path = $prefix === '' ? (string) $term->name : $prefix . ' / ' . $term->name;
+				$out[] = ['term' => $term, 'depth' => $depth, 'path' => $path];
+				$walk((int) $term->term_id, $depth + 1, $path);
+			}
+		};
+		$walk(0, 0, '');
+
+		return $out;
+	}
+
+	/**
+	 * @param array<string, mixed> $settings
+	 */
+	private static function signature(array $settings): string {
+		$whitelist = self::whitelist($settings);
+		sort($whitelist);
+		return implode(',', $whitelist);
+	}
+
+	private function __construct() {
+	}
+}
diff --git a/templates/parts/submit/context.php b/templates/parts/submit/context.php
index be2c4b62..4ff657c6 100644
--- a/templates/parts/submit/context.php
+++ b/templates/parts/submit/context.php
@@ -91,21 +91,10 @@ if ($edit_post) {
 }
 
 // Terms.
-$cat_args = [
-	'taxonomy'   => 'category',
-	'hide_empty' => false,
-	'orderby'    => 'name',
-	'order'      => 'ASC',
-];
-if (!empty($settings['allowed_cat_ids'])) {
-	$cat_args['include'] = $settings['allowed_cat_ids'];
-} else {
-	$cat_args['parent'] = 0;
-}
-$categories = get_terms($cat_args);
-if (is_wp_error($categories)) {
-	$categories = [];
-}
+$categories = array_map(
+	static fn(array $node): \WP_Term => $node['term'],
+	\Jio\Core\SubmitCategories::tree($settings)
+);
 $current_cats = $edit_post ? wp_get_post_categories($edit_post->ID) : [];
 
 $custom_dimensions = [];
diff --git a/tests/widget-system/creator-studio-contract.test.cjs b/tests/widget-system/creator-studio-contract.test.cjs
index d4ab7cf0..af4c4b7a 100644
--- a/tests/widget-system/creator-studio-contract.test.cjs
+++ b/tests/widget-system/creator-studio-contract.test.cjs
@@ -380,7 +380,6 @@ test('quote, hidden content, and block math render like the live article', () =>
 test('creator studio build artifacts and contracts exist', () => {
 	assert.ok(exists('assets/creator-studio/package.json'));
 	assert.ok(exists('assets/creator-studio/package-lock.json'));
-	assert.ok(exists('assets/creator-studio/build/.gitkeep'));
 	// build/ is gitignored and deploy-only (same as assets/admin/build); when a
 	// local build is present, all three entry artifacts must be there together.
 	const built = ['index.asset.php', 'index.js', 'index.css'];
@@ -507,6 +506,30 @@ test('publish settings use a multi-select category picker and a creatable tag in
 	assert.match(appSource, /suggestions: \(bootstrap\.tags && bootstrap\.tags\.suggestions\)/);
 });
 
+// 二级 / 三级分类必须出现在投稿页：列表是完整层级树，白名单向下展开到子分类。
+test('submit categories resolve the full hierarchy and expand the whitelist', () => {
+	const categories = read('src/Core/SubmitCategories.php');
+	const submitContext = read('templates/parts/submit/context.php');
+	const save = read('src/Core/FrontSubmitSave.php');
+
+	// 不再用 parent=0 过滤，改为取全部分类后按父子关系展平。
+	assert.doesNotMatch(categories, /'parent'\s*=>\s*0/);
+	assert.match(categories, /get_term_children\(\$id, 'category'\)/);
+	assert.match(categories, /'number'\s*=>\s*0/);
+	assert.match(categories, /'depth'\s*=>\s*\$depth/);
+	// 父级不在集合里时，子分类仍作为根节点出现，不会被静默丢弃。
+	assert.match(categories, /if \(!isset\(\$present\[\$parent\]\)\) \{/);
+
+	// 创作者工作台与经典投稿表单共用同一份分类数据。
+	assert.match(creatorRest, /SubmitCategories::tree\(\$settings\)/);
+	assert.match(submitContext, /SubmitCategories::tree\(\$settings\)/);
+	assert.doesNotMatch(submitContext, /\$cat_args\['parent'\]\s*=\s*0/);
+
+	// 白名单与审核应用都走同一套"含后代"的过滤。
+	assert.match(save, /SubmitCategories::filter_ids\(\$categories, \$settings\)/);
+	assert.match(versions, /SubmitCategories::filter_ids\(\$cats, \$settings\)/);
+});
+
 test('scheduled publishing is validated and applied server side', () => {
 	const save = read('src/Core/FrontSubmitSave.php');
 	const rest = read('src/Core/CreatorRest.php');
diff --git a/tests/widget-system/front-submit-pending-harness.php b/tests/widget-system/front-submit-pending-harness.php
index 4e02361b..c70d571f 100644
--- a/tests/widget-system/front-submit-pending-harness.php
+++ b/tests/widget-system/front-submit-pending-harness.php
@@ -34,10 +34,21 @@ namespace {
 		}
 	}
 
+	class WP_Term {
+		public int $term_id;
+		public string $name;
+		public int $parent;
+
+		public function __construct(int $term_id, string $name, int $parent = 0) {
+			$this->term_id = $term_id;
+			$this->name = $name;
+			$this->parent = $parent;
+		}
+	}
+
 	class WP_Error {
 		private string $code;
 		private string $message;
-
 		public function __construct($code = '', $message = '', $data = null) {
 			$this->code = (string) $code;
 			$this->message = (string) $message;
@@ -185,6 +196,13 @@ namespace {
 	function do_action($tag, ...$args): void { $GLOBALS['front_pending_state']['actions'][] = $tag; }
 	function current_time($type): string { return '2026-10-30 12:00:00'; }
 	function wp_set_post_categories($post_id, $categories): void {}
+	function get_terms($args = []) {
+		// 投稿分类解析需要一张分类表；本 harness 只关心上传生命周期，
+		// 给一个单层分类即可让白名单校验通过。
+		$term = new WP_Term(1, 'uncategorized', 0);
+		return [$term];
+	}
+	function get_term_children($term_id, $taxonomy) { return []; }
 	function wp_set_post_tags($post_id, $tags): void {}
 	function get_permalink($post_id): string { return 'https://example.test/?p=' . (int) $post_id; }
 	function clean_post_cache($post_id): void {}
@@ -334,6 +352,7 @@ namespace {
 	}
 
 	fp_reset();
+	require_once dirname(__DIR__, 2) . '/src/Core/SubmitCategories.php';
 	require_once dirname(__DIR__, 2) . '/src/Attachment/PendingUploads.php';
 	require_once dirname(__DIR__, 2) . '/src/Core/FrontSubmitSave.php';
 	require_once dirname(__DIR__, 2) . '/src/Core/FrontSubmitPay.php';