diff --git a/services/web/app/src/infrastructure/ExpressLocals.js b/services/web/app/src/infrastructure/ExpressLocals.js
index 17fdbab086..936453fe93 100644
--- a/services/web/app/src/infrastructure/ExpressLocals.js
+++ b/services/web/app/src/infrastructure/ExpressLocals.js
@@ -210,9 +210,10 @@ module.exports = function (webRouter, privateApiRouter, publicApiRouter) {
     ) {
       // Pick which main stylesheet to use based on Bootstrap version
       const bootstrap5Modifier = bootstrapVersion === 5 ? '-bootstrap-5' : ''
+      const computedThemeModifier = bootstrapVersion === 5 ? '' : themeModifier
 
       return res.locals.buildStylesheetPath(
-        `main-${themeModifier}style${bootstrap5Modifier}.css`
+        `main-${computedThemeModifier}style${bootstrap5Modifier}.css`
       )
     }
 
diff --git a/services/web/app/views/layout-base.pug b/services/web/app/views/layout-base.pug
index 944435317e..53e88d8131 100644
--- a/services/web/app/views/layout-base.pug
+++ b/services/web/app/views/layout-base.pug
@@ -73,7 +73,7 @@ html(
 
 		block head-scripts
 
-	body(class=(showThinFooter ? 'thin-footer' : undefined))
+	body(class=(showThinFooter ? 'thin-footer' : undefined), data-theme="default")
 		if(settings.recaptcha && settings.recaptcha.siteKeyV3)
 			script(type="text/javascript", nonce=scriptNonce, src="https://www.recaptcha.net/recaptcha/api.js?render=" + settings.recaptcha.siteKeyV3, defer=deferScripts)
 
diff --git a/services/web/frontend/js/features/editor-left-menu/hooks/use-set-overall-theme.tsx b/services/web/frontend/js/features/editor-left-menu/hooks/use-set-overall-theme.tsx
index 00634ea8d5..947bb9bc8d 100644
--- a/services/web/frontend/js/features/editor-left-menu/hooks/use-set-overall-theme.tsx
+++ b/services/web/frontend/js/features/editor-left-menu/hooks/use-set-overall-theme.tsx
@@ -6,6 +6,7 @@ import { saveUserSettings } from '../utils/api'
 import { UserSettings } from '../../../../../types/user-settings'
 import { useUserSettingsContext } from '@/shared/context/user-settings-context'
 import getMeta from '@/utils/meta'
+import { isBootstrap5 } from '@/features/utils/bootstrap-5'
 
 export default function useSetOverallTheme() {
   const [chosenTheme, setChosenTheme] = useState<OverallThemeMeta | null>(null)
@@ -23,7 +24,19 @@ export default function useSetOverallTheme() {
     [setUserSettings]
   )
 
+  const skipLoadingStyleSheet = isBootstrap5()
+
   useEffect(() => {
+    // Sets `data-theme` attribute to the body element, needed for Bootstrap 5 theming
+    const theme = overallTheme === 'light-' ? 'light' : 'default'
+    document.body.dataset.theme = theme
+  }, [overallTheme])
+
+  useEffect(() => {
+    if (skipLoadingStyleSheet) {
+      return
+    }
+
     const docHeadEl = document.querySelector('head')
     const oldStyleSheetEl = document.getElementById('main-stylesheet')
 
@@ -51,7 +64,12 @@ export default function useSetOverallTheme() {
     return () => {
       newStyleSheetEl.removeEventListener('load', loadEventCallback)
     }
-  }, [loadingStyleSheet, setLoadingStyleSheet, chosenTheme?.path])
+  }, [
+    loadingStyleSheet,
+    setLoadingStyleSheet,
+    skipLoadingStyleSheet,
+    chosenTheme?.path,
+  ])
 
   return useCallback(
     (newOverallTheme: UserSettings['overallTheme']) => {
@@ -62,13 +80,15 @@ export default function useSetOverallTheme() {
         )
 
         if (chosenTheme) {
-          setLoadingStyleSheet(true)
+          if (!skipLoadingStyleSheet) {
+            setLoadingStyleSheet(true)
+          }
           setChosenTheme(chosenTheme)
           setOverallTheme(newOverallTheme)
           saveUserSettings('overallTheme', newOverallTheme)
         }
       }
     },
-    [overallTheme, setLoadingStyleSheet, setOverallTheme]
+    [overallTheme, setLoadingStyleSheet, skipLoadingStyleSheet, setOverallTheme]
   )
 }
diff --git a/services/web/frontend/js/features/editor-navigation-toolbar/components/chat-toggle-button.jsx b/services/web/frontend/js/features/editor-navigation-toolbar/components/chat-toggle-button.jsx
index ee1926e1bf..1ebcdbe496 100644
--- a/services/web/frontend/js/features/editor-navigation-toolbar/components/chat-toggle-button.jsx
+++ b/services/web/frontend/js/features/editor-navigation-toolbar/components/chat-toggle-button.jsx
@@ -8,12 +8,7 @@ import OLBadge from '@/features/ui/components/ol/ol-badge'
 
 function ChatToggleButton({ chatIsOpen, unreadMessageCount, onClick }) {
   const { t } = useTranslation()
-  const classes = classNames(
-    'btn',
-    'btn-full-height',
-    'btn-full-height-no-border',
-    { active: chatIsOpen }
-  )
+  const classes = classNames('btn', 'btn-full-height', { active: chatIsOpen })
 
   const hasUnreadMessages = unreadMessageCount > 0
 
diff --git a/services/web/frontend/stylesheets/app/editor/toolbar.less b/services/web/frontend/stylesheets/app/editor/toolbar.less
index a41f2ee69d..d215966aba 100644
--- a/services/web/frontend/stylesheets/app/editor/toolbar.less
+++ b/services/web/frontend/stylesheets/app/editor/toolbar.less
@@ -118,10 +118,6 @@
       padding: 8px 10px;
     }
   }
-  .btn-full-height-no-border {
-    border-right: 0;
-    border-left: 0;
-  }
 
   .toolbar-left {
     display: flex;
diff --git a/services/web/frontend/stylesheets/bootstrap-5/abstracts/mixins.scss b/services/web/frontend/stylesheets/bootstrap-5/abstracts/mixins.scss
index 54cf94afcd..b2be7994eb 100644
--- a/services/web/frontend/stylesheets/bootstrap-5/abstracts/mixins.scss
+++ b/services/web/frontend/stylesheets/bootstrap-5/abstracts/mixins.scss
@@ -86,3 +86,13 @@
 @mixin file-tree-bg {
   background-color: var(--bg-dark-tertiary);
 }
+
+@mixin theme($name) {
+  @if index($themes, $name) {
+    [data-theme='#{$name}'] {
+      @content;
+    }
+  } @else {
+    @error 'Theme "#{$name}" is not supported. Supported themes are: #{$themes}.';
+  }
+}
diff --git a/services/web/frontend/stylesheets/bootstrap-5/abstracts/variables.scss b/services/web/frontend/stylesheets/bootstrap-5/abstracts/variables.scss
index 62f20c9be8..ad92e08c3c 100644
--- a/services/web/frontend/stylesheets/bootstrap-5/abstracts/variables.scss
+++ b/services/web/frontend/stylesheets/bootstrap-5/abstracts/variables.scss
@@ -6,3 +6,6 @@ $header-height: 68px;
 
 // Forms
 $form-group-margin-bottom: $spacing-06;
+
+// List of allowed themes
+$themes: ('default', 'light');
diff --git a/services/web/frontend/stylesheets/bootstrap-5/base/bootstrap.scss b/services/web/frontend/stylesheets/bootstrap-5/base/bootstrap.scss
index 97fb2f79d1..b486476f67 100644
--- a/services/web/frontend/stylesheets/bootstrap-5/base/bootstrap.scss
+++ b/services/web/frontend/stylesheets/bootstrap-5/base/bootstrap.scss
@@ -56,5 +56,8 @@
 // Custom helpers
 @import '../helpers/all';
 
+// Modals
+@import '../modals/all';
+
 // Pages custom style
 @import '../pages/all';
diff --git a/services/web/frontend/stylesheets/bootstrap-5/main-ieee-style.scss b/services/web/frontend/stylesheets/bootstrap-5/main-ieee-style.scss
deleted file mode 100644
index 0c2708007b..0000000000
--- a/services/web/frontend/stylesheets/bootstrap-5/main-ieee-style.scss
+++ /dev/null
@@ -1,4 +0,0 @@
-@import 'main-style';
-
-// IEEE-specific rules
-$ieee-wedge: 30px;
diff --git a/services/web/frontend/stylesheets/bootstrap-5/main-light-style.scss b/services/web/frontend/stylesheets/bootstrap-5/main-light-style.scss
deleted file mode 100644
index 2463ed9611..0000000000
--- a/services/web/frontend/stylesheets/bootstrap-5/main-light-style.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-@import 'main-style';
-
-$is-overleaf-light: true;
diff --git a/services/web/frontend/stylesheets/bootstrap-5/main-style.scss b/services/web/frontend/stylesheets/bootstrap-5/main-style.scss
index 5f4635ab9c..0060b630bb 100644
--- a/services/web/frontend/stylesheets/bootstrap-5/main-style.scss
+++ b/services/web/frontend/stylesheets/bootstrap-5/main-style.scss
@@ -8,8 +8,6 @@
 @import '../../fonts/material-symbols';
 @import '../../fonts/font-awesome';
 
-$is-overleaf-light: false;
-
 // Vendor CSS
 // TODO Bootstrap 5: Check whether this works with Bootstrap 5, and whether we can replace it
 @import '../vendor/select/select';
@@ -32,9 +30,3 @@ $is-overleaf-light: false;
 
 // Page layout that isn't related to a particular component or page
 @import 'base/layout';
-
-// Modals
-@import 'modals/all';
-
-// Pages custom style
-@import 'pages/all';
diff --git a/services/web/frontend/stylesheets/bootstrap-5/pages/editor/online-users.scss b/services/web/frontend/stylesheets/bootstrap-5/pages/editor/online-users.scss
index c67e6da3b4..52265c6e97 100644
--- a/services/web/frontend/stylesheets/bootstrap-5/pages/editor/online-users.scss
+++ b/services/web/frontend/stylesheets/bootstrap-5/pages/editor/online-users.scss
@@ -2,6 +2,10 @@
   --toolbar-btn-color: var(--white);
 }
 
+@include theme('light') {
+  --toolbar-btn-color: var(--neutral-70);
+}
+
 .online-users {
   display: flex;
   align-items: center;
diff --git a/services/web/frontend/stylesheets/bootstrap-5/pages/editor/review-panel.scss b/services/web/frontend/stylesheets/bootstrap-5/pages/editor/review-panel.scss
index d7ff2e93c2..0aee1bdf17 100644
--- a/services/web/frontend/stylesheets/bootstrap-5/pages/editor/review-panel.scss
+++ b/services/web/frontend/stylesheets/bootstrap-5/pages/editor/review-panel.scss
@@ -2,6 +2,19 @@
   --review-icon: url('../../../../../public/img/ol-icons/review-icon-dark-theme.svg');
 }
 
+@include theme('light') {
+  --review-icon: url('../../../../../public/img/ol-icons/review-icon-light-theme.svg');
+
+  button {
+    &.active,
+    &:active {
+      .review-icon {
+        --review-icon: url('../../../../../public/img/ol-icons/review-icon-dark-theme.svg');
+      }
+    }
+  }
+}
+
 .review-icon {
   display: inline-block;
   background-image: var(--review-icon);
diff --git a/services/web/frontend/stylesheets/bootstrap-5/pages/editor/toolbar.scss b/services/web/frontend/stylesheets/bootstrap-5/pages/editor/toolbar.scss
index 3b52ed15b7..1500e978f5 100644
--- a/services/web/frontend/stylesheets/bootstrap-5/pages/editor/toolbar.scss
+++ b/services/web/frontend/stylesheets/bootstrap-5/pages/editor/toolbar.scss
@@ -11,6 +11,19 @@
     center / contain no-repeat;
 }
 
+@include theme('light') {
+  --toolbar-border-color: var(--neutral-20);
+  --toolbar-header-bg-color: var(--white);
+  --toolbar-header-btn-border-color: var(--neutral-20);
+  --toolbar-btn-color: var(--neutral-70);
+  --toolbar-btn-hover-bg-color: var(--neutral-10);
+  --project-name-color: var(--neutral-70);
+  --project-rename-link-color: var(--neutral-70);
+  --project-rename-link-color-hover: var(--neutral-70);
+  --editor-header-logo-background: url(../../../../../public/img/ol-brand/overleaf-o.svg)
+    center / contain no-repeat;
+}
+
 .toolbar {
   --toolbar-height: 40px;
 
@@ -37,7 +50,7 @@
 
   .toolbar-right,
   .toolbar-left {
-    button {
+    button:not(.back-to-editor-btn) {
       background: transparent;
       box-shadow: none;
     }
@@ -51,7 +64,7 @@
   button.btn-full-height {
     border: none;
     border-radius: 0;
-    border-right: 1px solid var(--toolbar-header-btn-border-color) !important;
+    border-right: 1px solid var(--toolbar-header-btn-border-color);
     color: var(--toolbar-btn-color);
     padding: var(--spacing-02) var(--spacing-05) var(--spacing-03);
     font-size: var(--font-size-05);
@@ -95,11 +108,6 @@
     }
   }
 
-  .btn-full-height-no-border {
-    border-right: 0;
-    border-left: 0;
-  }
-
   .toolbar-left {
     display: flex;
     align-items: stretch;
@@ -113,7 +121,8 @@
     flex-grow: 1;
     justify-content: flex-end;
 
-    .btn-full-height {
+    a.btn-full-height,
+    button.btn-full-height {
       border-right: 0;
       border-left: 1px solid var(--toolbar-header-btn-border-color);
     }
diff --git a/services/web/webpack.config.js b/services/web/webpack.config.js
index 52e28f8d2f..002cfda877 100644
--- a/services/web/webpack.config.js
+++ b/services/web/webpack.config.js
@@ -27,10 +27,6 @@ const entryPoints = {
   'main-light-style': './frontend/stylesheets/main-light-style.less',
   'main-style-bootstrap-5':
     './frontend/stylesheets/bootstrap-5/main-style.scss',
-  'main-ieee-style-bootstrap-5':
-    './frontend/stylesheets/bootstrap-5/main-ieee-style.scss',
-  'main-light-style-bootstrap-5':
-    './frontend/stylesheets/bootstrap-5/main-light-style.scss',
 }
 
 // Add entrypoints for each "page"