diff --git a/packages/hydrooj/src/service/server.ts b/packages/hydrooj/src/service/server.ts
index 4e028b0bb..1b7a49308 100644
--- a/packages/hydrooj/src/service/server.ts
+++ b/packages/hydrooj/src/service/server.ts
@@ -823,8 +823,8 @@ export class ConnectionHandler extends HandlerCommon {
     onerror(err: HydroError) {
         if (err instanceof UserFacingError) err.stack = this.conn.pathname;
         if (!(err instanceof NotFoundError)
-            && !((err instanceof PrivilegeError || err instanceof PermissionError) && this.user._id === 0)) {
-            logger.error(`Path:${this.conn.pathname}, User:${this.user._id}(${this.user.uname})`);
+            && !((err instanceof PrivilegeError || err instanceof PermissionError) && this.user?._id === 0)) {
+            logger.error(`Path:${this.conn.pathname}, User:${this.user?._id}(${this.user?.uname})`);
             logger.error(err);
         }
         this.send({
diff --git a/packages/ui-default/handler.ts b/packages/ui-default/handler.ts
index 9f671e777..2dceea0ca 100644
--- a/packages/ui-default/handler.ts
+++ b/packages/ui-default/handler.ts
@@ -172,7 +172,7 @@ class RichMediaHandler extends Handler {
 global.Hydro.handler.ui = async () => {
   Route('wiki_help', '/wiki/help', WikiHelpHandler);
   Route('wiki_about', '/wiki/about', WikiAboutHandler);
-  Route('set_theme', '/set_theme/:id', SetThemeHandler);
+  Route('set_theme', '/set_theme/:theme', SetThemeHandler);
   Route('constant', '/constant', UiConstantsHandler);
   Route('markdown', '/markdown', MarkdownHandler);
   Route('lang', '/l/:lang', LanguageHandler);
diff --git a/packages/ui-default/package.json b/packages/ui-default/package.json
index a0557a92c..a9a0b588f 100644
--- a/packages/ui-default/package.json
+++ b/packages/ui-default/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@hydrooj/ui-default",
-  "version": "4.34.6",
+  "version": "4.34.7",
   "author": "undefined <i@undefined.moe>",
   "license": "AGPL-3.0",
   "main": "hydro.js",
diff --git a/packages/ui-default/setting.yaml b/packages/ui-default/setting.yaml
index cda81e532..bb43f8fcd 100644
--- a/packages/ui-default/setting.yaml
+++ b/packages/ui-default/setting.yaml
@@ -62,6 +62,13 @@ monacoTheme:
   category: preference
   value: vs-light
   family: markdown
+theme:
+  type:
+    light: Light
+    dark: Dark
+  category: preference
+  value: light
+  family: setting_display
 showInvisibleChar:
   type: boolean
   family: highlight
diff --git a/packages/ui-default/templates/layout/html5.html b/packages/ui-default/templates/layout/html5.html
index 3256ad80c..67883ebcf 100644
--- a/packages/ui-default/templates/layout/html5.html
+++ b/packages/ui-default/templates/layout/html5.html
@@ -5,7 +5,7 @@
 {% import "components/noscript_note.html" as noscript_note with context %}
 {% import "components/user.html" as user with context %}
 <!DOCTYPE html>
-<html data-page="{{ page_name }}" data-layout="{{ layout_name }}" class="layout--{{ layout_name }} page--{{ page_name }} nojs" lang="{{ handler.viewLang }}" data-app="Hydro">
+<html data-page="{{ page_name }}" data-layout="{{ layout_name }}" class="layout--{{ layout_name }} page--{{ page_name }} theme--{{ (handler.user|default({})).theme|default('default') }} nojs" lang="{{ handler.viewLang }}" data-app="Hydro">
 <head>
   <meta charset="UTF-8">
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
@@ -35,7 +35,7 @@
   {% if process.env.DEV %}
     <link rel="stylesheet" media="all" href="/default.theme.css">
   {% else %}
-    <link rel="stylesheet" media="all" href="{{ static_url((handler.user|default({})).theme|default('default') + '-' + global.Hydro.version['ui-default'] +'.theme.css') }}">
+    <link rel="stylesheet" media="all" href="{{ static_url('default-' + global.Hydro.version['ui-default'] +'.theme.css') }}">
   {% endif %}
   {% if not isIE(handler.request.headers['user-agent']) %}
     <script>
@@ -71,7 +71,7 @@
       <script type="module" src="http://localhost:3000/@vite/client"></script>
       <script type="module" src="http://localhost:3000/entry.js"></script>
     {% else %}
-      <script src="{{ static_url((handler.user|default({})).theme|default('default') + '.theme.js') }}?version={{ global.Hydro.version['ui-default'] }}"></script>
+      <script src="{{ static_url('default.theme.js') }}?version={{ global.Hydro.version['ui-default'] }}"></script>
       {% if process.env.DEV %}
         <script type="text/javascript" src="/hydro.js"></script>
       {% else %}
diff --git a/packages/ui-default/templates/partials/footer.html b/packages/ui-default/templates/partials/footer.html
index 62c9f441c..59cae78df 100644
--- a/packages/ui-default/templates/partials/footer.html
+++ b/packages/ui-default/templates/partials/footer.html
@@ -61,9 +61,8 @@
           <li class="footer__extra-link-item" data-dropdown-target="#menu-footer-theme">
             <span><span class="icon icon-global"></span> Theme <span class="icon icon-expand_less"></span></span>
             <ol class="dropdown-target menu" id="menu-footer-theme">
-            {%- for k in UiContext.themes -%}
-              <li class="menu__item"><a class="menu__link" href="{{ url('set_theme', id=k) }}">{{ k }}</a></li>
-            {%- endfor -%}
+              <li class="menu__item"><a class="menu__link" href="{{ url('set_theme', id='light') }}">Light</a></li>
+              <li class="menu__item"><a class="menu__link" href="{{ url('set_theme', id='dark') }}">Dark</a></li>
             </ol>
           </li>
         </ol>
diff --git a/packages/ui-default/theme/dark.styl b/packages/ui-default/theme/dark.styl
new file mode 100644
index 000000000..3376b3a1f
--- /dev/null
+++ b/packages/ui-default/theme/dark.styl
@@ -0,0 +1,348 @@
+.theme--dark
+  #panel
+    background-color: #1d2022
+
+  .nav
+    background-color: rgba(15, 15, 15, 98)
+
+  .nav .nav__item:hover
+    background-color: #171717
+
+  .nav .nav__item
+    color: #aaa
+
+  .section
+    background-color: #1f1f1f
+    box-shadow: 0 0.2rem 0.5rem #3d3d3d
+
+  body
+    color: #d9dfe7
+
+  .footer
+    background-color: #1f1f1f
+    color: #aaa
+
+  h1, h2, h3, h4, h5, h6
+    color: #c2c2c2
+
+  a, .link, a:visited, .link:visited, a:hover, .link:hover, a:active, .link:active
+    color: #aaa
+
+  .section__title
+    color: #9b9b9b
+
+  .dropdown .menu
+    box-shadow: 0 0.125rem 0.4375rem #3d3d3d
+    background-color: rgb(15, 15, 15)
+
+  a.menu__link:not(.disabled):hover, button.menu__link:not(.disabled):hover
+    color: #aaa
+    background-color: rgb(27, 27, 27)
+
+  blockquote, blockquote.blue, blockquote.red, blockquote.yellow, blockquote.warn, blockquote.note
+    background-color: rgb(23, 23, 23)
+    color: #999
+
+  blockquote
+    border-left-color: #323232
+
+  a.menu__link.active, button.menu__link.active, a.menu__link.active:hover, button.menu__link.active:hover
+    background-color: #ed5f82
+    color: #fff
+
+  .menu__seperator
+    border-top-color: #212121
+
+  .menu__link
+    color: #aaa
+
+  .button:not(.codicon)
+    background-color: #212121
+    border: 1px solid #323232
+
+  .button:not(.codicon),.button:not(.codicon):visited,.button:not(.codicon):hover,.typo .button:not(.codicon),.typo .button:not(.codicon):visited,.typo .button:not(.codicon):hover
+    color: #aaa
+
+  .button:not(.codicon):not(.disabled):hover,.button:not(.codicon):not(.disabled):focus
+    background-color: #3d3d3d
+    border-color: #3d3d3d
+    box-shadow: 0 4px 15px rgba(56,56,56,.5)
+
+  .dialog
+    background-color: rgba(31, 31, 31, 0.6)
+
+  .dialog.withBg .dialog__content
+    background-color: #1f1f1f
+    border: 1px solid #323232
+    box-shadow: 0 0.125rem 0.625rem rgba(255 255 255 20%)
+
+  .section__table-header
+    background-color: rgba(15, 15, 15, 0.95)
+    box-shadow: 0 0.1875rem 0.125rem rgba(255 255 255 3%)
+
+  .data-table tr
+    border-top: 1px solid #2b2b2b
+    border-bottom: 1px solid #2b2b2b
+
+  .checkbox input
+    border-color: #3f3f3f
+
+  .data-table tr:nth-child(even)
+    background-color: #1b1b1b
+
+  .page--problem_main .col--ac-tried, .page--problem_category .col--ac-tried
+    border-left-color: #2b2b2b
+
+  .page--problem_main .col--status, .page--problem_category .col--status
+    border-right-color: #2b2b2b !important
+
+  .pager.pager-top
+    border-bottom-color: #2b2b2b
+    .pager__item
+      border-bottom-color: #2b2b2b
+
+  .pager.pager-bottom
+    border-top-color: #2b2b2b
+    .pager__item
+      border-top-color: #2b2b2b
+
+  input
+    background-color: #1f1f1f
+
+  .search>input
+    border-color: #434343
+    border-top-color: rgb(67, 67, 67)
+    border-bottom-color: rgb(67, 67, 67)
+    border-left-color: rgb(67, 67, 67)
+    color: #fff
+
+  .select
+    border: 1px solid #323232
+    background-color: #1f1f1f
+
+  .select:focus
+    border-color: #2960a0
+    outline-color: #102f4e
+
+  .page--record_main .col--status, .page--record_main .col--submit-by, .page--record_main .col--lang
+    border-right-color: #2b2b2b
+
+  .page--home_domain .col--role
+    border-left: 1px solid #2b2b2b
+    border-left-color: rgb(43, 43, 43)
+
+  input.textbox, textarea.textbox
+    border: 1px solid #323232
+    background-color: #1f1f1f
+
+  .autocomplete-wrapper input
+    background-color: #1f1f1f
+    color: rgba(255,255,255,.85)
+
+  .autocomplete-wrapper
+    border-color: #363636
+    background-color: #1f1f1f
+
+  label:not(.quick-input-list-label)
+    color: #999
+
+  .scratchpad-container
+    background-color: #1f1f1f
+
+  .toolbar
+    background-color: rgba(23, 23, 23, 0.8)
+
+  pre[class*=language-]
+    border: 1px solid #323232
+    background-color: #1f1f1f
+
+  code[class*=language-], pre[class*=language-]
+    color: #cbc5c6
+
+  pre[class*=language-]::-moz-selection,pre[class*=language-] ::-moz-selection,code[class*=language-]::-moz-selection,code[class*=language-] ::-moz-selection
+    background-color: #ADD6FF26
+
+  pre[class*=language-]::selection,pre[class*=language-] ::selection,code[class*=language-]::selection,code[class*=language-] ::selection
+    background-color: #ADD6FF26
+
+  :not(pre)>code[class*=language-]
+    background-color: #171717
+    border: 1px solid #323232
+
+  .scratchpad__data-input
+    border-left-color: #2f2f2f
+    background-color: #171717
+    color: #999
+
+  pre, code
+    background-color: #171717
+
+  .scratchpad__toolbar
+    background-color: #18191d
+
+  .scratchpad__toolbar__button.enabled:hover
+    color: #8a94a5
+    background-color: #27282c
+
+  .scratchpad__toolbar__split
+    background-color: #313131
+
+  .menu__link.highlight
+    background: rgb(40, 11, 20)
+
+  .bp3-tag.bp3-minimal:not([class*="bp3-intent-"])
+    background-color: rgba(87, 100, 117, .2)
+    color: #d9dfe7
+
+  .typo table thead th
+    background: #1e1e1e
+    background-color: rgb(30, 30, 30)
+
+  .typo table th, .typo table td, .typo table caption
+    border-color: #323232
+    color: #999
+
+  body>.marker
+    box-shadow: 0 2px 7px rgba(255 255 255 30%)
+    background-color: #1f1f1f
+    border-color: #555
+
+  body>.marker .marker__toolbar
+    background-color: #18191d
+
+  .messagepad__sidebar
+    border-right-color: #212121
+
+  .messagepad__list-item:hover
+    border-color: #323232
+    background-color: #1b1b1b
+
+  .messagepad__list-item.active
+    border-color: #ed5f82
+    background-color: rgba(237,95,130,.07)
+
+  .messagepad__input
+    border-top-color: #212121
+
+  .section__tab-container.immersive .section__tab-header-item.selected
+    background-color: rgb(15, 15, 15)
+    color: #999
+    box-shadow: 0 0 10px rgba(255 255 255 30%)
+
+  .dialog--signin__main
+    background-color: #1f1f1f
+    box-shadow: 0 0 30px rgba(255 255 255 60%)
+
+  .nothing-icon
+    filter: brightness(50%)
+
+  .scratchpad__data-input:focus
+    background: #1f1f1f
+    border-color: #1c2d40
+
+  .section__list__item
+    border-bottom-color: #2b2b2b
+
+  .autocomplete-list
+    background-color: #1f1f1f
+    li[aria-selected=true]
+      background-color: #151515
+    li[data-focus=true]
+      background-color: #101829
+      cursor: pointer
+
+  .dczcomments__item, .dczcomments__reply
+    border-top-color: #2b2b2b
+
+  .autocomplete-tag
+    background-color: #ff0000
+
+  .problem__tag-link
+    background-color: #1f1f1f
+    color: #aaa!important
+
+  label.textbox.material input
+    border-color: #333
+    color: #aaa
+    border-bottom-color: rgba(170,170,170,.4)
+
+  .widget--category-filter__drop
+    background-color: #1f1f1f
+    box-shadow: 0 0.125rem 0.4375rem rgba(255 255 255 30%)
+
+  hr
+    border-bottom-color: #404040
+
+  .section__footer
+    border-top-color: #2b2b2b
+
+  .page--discussion_detail .sidebar-user-profile .user-profile-name, .page--blog_detail .sidebar-user-profile .user-profile-name
+    color: #bbb
+
+  .page--record_detail .col--case, .page--record_detail .col--status
+    border-right-color: #2b2b2b
+
+  .data-table thead>tr
+    border-bottom-color: #2b2b2b
+
+  .token.comment,.token.prolog,.token.doctype,.token.cdata
+    color: #57A64A
+    font-style: italic
+
+  .token.namespace
+    opacity: .7
+
+  .token.string
+    color: #D69D85
+
+  .token.punctuation,.token.operator
+    color: #B4B4B4
+
+  .token.url,.token.symbol,.token.number,.token.boolean,.token.variable,.token.constant,.token.inserted
+    color: #B5CEA8
+
+  .token.atrule,.token.keyword,.token.attr-value,.language-autohotkey .token.selector,.language-json .token.boolean,.language-json .token.number,code[class*=language-css]
+    color: #569cd6
+
+  .token.function
+    color: #C8C8C8
+
+  .token.deleted,.language-autohotkey .token.tag
+    color: #9a050f
+
+  .token.selector,.language-autohotkey .token.keyword
+    color: #00009f
+
+  .token.important
+    color: #e90
+
+  .token.important,.token.bold
+    font-weight: 700
+
+  .token.italic
+    font-style: italic
+
+  .token.class-name,.language-json .token.property
+    color: #4EC9B0
+
+  .token.tag,.token.selector
+    color: #d7ba7d
+
+  .token.attr-name,.token.property,.token.regex,.token.entity
+    color: #d16969
+
+  .token.directive.tag .tag
+    background: #ffff00
+    color: #393a34
+
+  .page--problem_edit .section__tab-header-item:hover
+    background-color: #171717
+
+  .page--home_security .sessionlist__item
+    border-bottom-color: #323232
+
+  @media only screen and (max-width: 600px) {
+    .footer__category {
+      border-bottom-color: #1d1d1d
+    }
+  }
diff --git a/packages/ui-default/theme/default.js b/packages/ui-default/theme/default.js
index 3b329a939..c53a9f24f 100644
--- a/packages/ui-default/theme/default.js
+++ b/packages/ui-default/theme/default.js
@@ -36,3 +36,5 @@ const pageStyleReq = require.context('../', true, /\.page\.styl$/i);
 pageStyleReq.keys().map((key) => pageStyleReq(key));
 const pageStyleReqDefault = require.context('../', true, /\.page\.default\.styl$/i);
 pageStyleReqDefault.keys().map((key) => pageStyleReqDefault(key));
+
+import './dark.styl';