diff --git a/app/javascript/mastodon/features/hashtag_timeline/components/column_settings.js b/app/javascript/mastodon/features/hashtag_timeline/components/column_settings.js
index 956f167340a..27300f020df 100644
--- a/app/javascript/mastodon/features/hashtag_timeline/components/column_settings.js
+++ b/app/javascript/mastodon/features/hashtag_timeline/components/column_settings.js
@@ -4,6 +4,7 @@ import ImmutablePropTypes from 'react-immutable-proptypes';
 import { defineMessages, injectIntl, FormattedMessage } from 'react-intl';
 import Toggle from 'react-toggle';
 import AsyncSelect from 'react-select/async';
+import { NonceProvider } from 'react-select';
 import SettingToggle from '../../notifications/components/setting_toggle';
 
 const messages = defineMessages({
@@ -58,18 +59,20 @@ class ColumnSettings extends React.PureComponent {
           {this.modeLabel(mode)}
         </span>
 
-        <AsyncSelect
-          isMulti
-          autoFocus
-          value={this.tags(mode)}
-          onChange={this.onSelect(mode)}
-          loadOptions={this.props.onLoad}
-          className='column-select__container'
-          classNamePrefix='column-select'
-          name='tags'
-          placeholder={this.props.intl.formatMessage(messages.placeholder)}
-          noOptionsMessage={this.noOptionsMessage}
-        />
+        <NonceProvider nonce={document.querySelector('meta[name=style-nonce]').content}>
+          <AsyncSelect
+            isMulti
+            autoFocus
+            value={this.tags(mode)}
+            onChange={this.onSelect(mode)}
+            loadOptions={this.props.onLoad}
+            className='column-select__container'
+            classNamePrefix='column-select'
+            name='tags'
+            placeholder={this.props.intl.formatMessage(messages.placeholder)}
+            noOptionsMessage={this.noOptionsMessage}
+          />
+        </NonceProvider>
       </div>
     );
   }
diff --git a/app/views/layouts/application.html.haml b/app/views/layouts/application.html.haml
index 39fa0678fdc..e32cdcabb3f 100755
--- a/app/views/layouts/application.html.haml
+++ b/app/views/layouts/application.html.haml
@@ -25,6 +25,7 @@
     = javascript_pack_tag 'common', integrity: true, crossorigin: 'anonymous'
     = javascript_pack_tag "locale_#{I18n.locale}", integrity: true, crossorigin: 'anonymous'
     = csrf_meta_tags
+    %meta{ name: 'style-nonce', content: request.content_security_policy_nonce }
 
     = stylesheet_link_tag '/inert.css', skip_pipeline: true, media: 'all', id: 'inert-style'
 
diff --git a/config/initializers/content_security_policy.rb b/config/initializers/content_security_policy.rb
index 7dcc028ab6a..98dc711e1b8 100644
--- a/config/initializers/content_security_policy.rb
+++ b/config/initializers/content_security_policy.rb
@@ -47,7 +47,25 @@ end
 # https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy-Report-Only
 # Rails.application.config.content_security_policy_report_only = true
 
+Rails.application.config.content_security_policy_nonce_generator = -> request { SecureRandom.base64(16) }
+
+# Monkey-patching Rails 5
+module ActionDispatch
+  class ContentSecurityPolicy
+    def nonce_directive?(directive)
+      directive == 'style-src'
+    end
+  end
+end
+
+# Rails 6 would require the following instead:
+# Rails.application.config.content_security_policy_nonce_directives = %w(style-src)
+
 PgHero::HomeController.content_security_policy do |p|
   p.script_src :self, :unsafe_inline, assets_host
   p.style_src  :self, :unsafe_inline, assets_host
 end
+
+PgHero::HomeController.after_action do
+  request.content_security_policy_nonce_generator = nil
+end