Dark theme is not applied to addons.mozilla.org

### Describe the bug

I set dark_mode according to the wiki using these:
```
user_pref("userContent.page.proton", true);
user_pref("userContent.page.dark_mode", true);
```
And I restarted my browser, the addons.mozilla.org still uses light theme. support.mozilla.org and accounts.firefox.com too.

### Expected behavior

At least the dark theme should be set when system uses dark theme on these pages.

### Screenshots

### OS

Linux

### OS - Others

_No response_

### Firefox Version

v147.0b1

### Distribution

- [x] [Original Lepton](https://github.com/black7375/Firefox-UI-Fix)
- [ ] [Lepton's photon style](https://github.com/black7375/Firefox-UI-Fix/tree/photon-style)
- [ ] [Lepton's proton style](https://github.com/black7375/Firefox-UI-Fix/tree/proton-style)

### Theme

- [ ] Light
- [ ] Dark
- [ ] Alpenglow (System: Light)
- [ ] Alpenglow (System: Dark)
- [x] System Default
- [ ] Others: (e.g. [Photon Colors](https://addons.mozilla.org/en-US/firefox/addon/photon-colors/), [Google Chrome Dark](https://addons.mozilla.org/en-US/firefox/addon/google-chrome-dark/), [Fairytale Of Nature](https://addons.mozilla.org/en-US/firefox/addon/fairytale-of-nature/))

### Theme - More Info

- Breeze

### `user.js` setup

user.js setup

```javascript
//
/* You may copy+paste this file and use it as it is.
*
* If you make changes to your about:config while the program is running, the
* changes will be overwritten by the user.js when the application restarts.
*
* To make lasting changes to preferences, you will have to edit the user.js.
*/

/****************************************************************************
* Betterfox *
* "Ad meliora" *
* version: 146 *
* url: https://github.com/yokoffing/Betterfox *
****************************************************************************/

/****************************************************************************
* SECTION: FASTFOX *
****************************************************************************/
/** GENERAL ***/
user_pref("gfx.content.skia-font-cache-size", 32);

/** GFX ***/
user_pref("gfx.canvas.accelerated.cache-items", 32768);
user_pref("gfx.canvas.accelerated.cache-size", 4096);
user_pref("webgl.max-size", 16384);

/** DISK CACHE ***/
user_pref("browser.cache.disk.enable", false);

/** MEMORY CACHE ***/
user_pref("browser.cache.memory.capacity", 131072);
user_pref("browser.cache.memory.max_entry_size", 20480);
user_pref("browser.sessionhistory.max_total_viewers", 4);
user_pref("browser.sessionstore.max_tabs_undo", 10);

/** MEDIA CACHE ***/
user_pref("media.memory_cache_max_size", 262144);
user_pref("media.memory_caches_combined_limit_kb", 1048576);
user_pref("media.cache_readahead_limit", 600);
user_pref("media.cache_resume_threshold", 300);

/** IMAGE CACHE ***/
user_pref("image.cache.size", 10485760);
user_pref("image.mem.decode_bytes_at_a_time", 65536);

/** NETWORK ***/
user_pref("network.http.max-connections", 1800);
user_pref("network.http.max-persistent-connections-per-server", 10);
user_pref("network.http.max-urgent-start-excessive-connections-per-host", 5);
user_pref("network.http.request.max-start-delay", 5);
user_pref("network.http.pacing.requests.enabled", false);
user_pref("network.dnsCacheEntries", 10000);
user_pref("network.dnsCacheExpiration", 3600);
user_pref("network.ssl_tokens_cache_capacity", 10240);

/** SPECULATIVE LOADING ***/
user_pref("network.http.speculative-parallel-limit", 0);
user_pref("network.dns.disablePrefetch", true);
user_pref("network.dns.disablePrefetchFromHTTPS", true);
user_pref("browser.urlbar.speculativeConnect.enabled", false);
user_pref("browser.places.speculativeConnect.enabled", false);
user_pref("network.prefetch-next", false);

/****************************************************************************
* SECTION: SECUREFOX *
****************************************************************************/
/** TRACKING PROTECTION ***/
user_pref("browser.contentblocking.category", "strict");
user_pref("browser.download.start_downloads_in_tmp_dir", true);
user_pref("browser.uitour.enabled", false);
user_pref("privacy.globalprivacycontrol.enabled", true);

/** OCSP & CERTS / HPKP ***/
user_pref("security.OCSP.enabled", 0);
user_pref("privacy.antitracking.isolateContentScriptResources", true);
user_pref("security.csp.reporting.enabled", false);

/** SSL / TLS ***/
user_pref("security.ssl.treat_unsafe_negotiation_as_broken", true);
user_pref("browser.xul.error_pages.expert_bad_cert", true);
user_pref("security.tls.enable_0rtt_data", false);

/** DISK AVOIDANCE ***/
user_pref("browser.privatebrowsing.forceMediaMemoryCache", true);
user_pref("browser.sessionstore.interval", 60000);

/** SHUTDOWN & SANITIZING ***/
user_pref("privacy.history.custom", true);
user_pref("browser.privatebrowsing.resetPBM.enabled", true);

/** SEARCH / URL BAR ***/
user_pref("browser.urlbar.trimHttps", true);
user_pref("browser.urlbar.untrimOnUserInteraction.featureGate", true);
user_pref("browser.search.separatePrivateDefault.ui.enabled", true);
user_pref("browser.search.suggest.enabled", false);
user_pref("browser.urlbar.quicksuggest.enabled", false);
user_pref("browser.urlbar.groupLabels.enabled", false);
user_pref("browser.formfill.enable", false);
user_pref("network.IDN_show_punycode", true);

/** HTTPS-ONLY MODE ***/
user_pref("dom.security.https_only_mode", true);
user_pref("dom.security.https_only_mode_error_page_user_suggestions", true);

/** PASSWORDS ***/
user_pref("signon.formlessCapture.enabled", false);
user_pref("signon.privateBrowsingCapture.enabled", false);
user_pref("network.auth.subresource-http-auth-allow", 1);
user_pref("editor.truncate_user_pastes", false);

/** EXTENSIONS ***/
user_pref("extensions.enabledScopes", 5);

/** HEADERS / REFERERS ***/
user_pref("network.http.referer.XOriginTrimmingPolicy", 2);

/** CONTAINERS ***/
user_pref("privacy.userContext.ui.enabled", true);

/** VARIOUS ***/
user_pref("pdfjs.enableScripting", false);

/** SAFE BROWSING ***/
user_pref("browser.safebrowsing.downloads.remote.enabled", false);

/** MOZILLA ***/
user_pref("permissions.default.desktop-notification", 2);
user_pref("permissions.default.geo", 2);
user_pref("geo.provider.network.url", "https://beacondb.net/v1/geolocate");
user_pref("browser.search.update", false);
user_pref("permissions.manager.defaultsUrl", "");
user_pref("extensions.getAddons.cache.enabled", false);

/** TELEMETRY ***/
user_pref("datareporting.policy.dataSubmissionEnabled", false);
user_pref("datareporting.healthreport.uploadEnabled", false);
user_pref("toolkit.telemetry.unified", false);
user_pref("toolkit.telemetry.enabled", false);
user_pref("toolkit.telemetry.server", "data:,");
user_pref("toolkit.telemetry.archive.enabled", false);
user_pref("toolkit.telemetry.newProfilePing.enabled", false);
user_pref("toolkit.telemetry.shutdownPingSender.enabled", false);
user_pref("toolkit.telemetry.updatePing.enabled", false);
user_pref("toolkit.telemetry.bhrPing.enabled", false);
user_pref("toolkit.telemetry.firstShutdownPing.enabled", false);
user_pref("toolkit.telemetry.coverage.opt-out", true);
user_pref("toolkit.coverage.opt-out", true);
user_pref("toolkit.coverage.endpoint.base", "");
user_pref("browser.newtabpage.activity-stream.feeds.telemetry", false);
user_pref("browser.newtabpage.activity-stream.telemetry", false);
user_pref("datareporting.usage.uploadEnabled", false);

/** EXPERIMENTS ***/
user_pref("app.shield.optoutstudies.enabled", false);
user_pref("app.normandy.enabled", false);
user_pref("app.normandy.api_url", "");

/** CRASH REPORTS ***/
user_pref("breakpad.reportURL", "");
user_pref("browser.tabs.crashReporting.sendReport", false);

/****************************************************************************
* SECTION: PESKYFOX *
****************************************************************************/
/** MOZILLA UI ***/
user_pref("extensions.getAddons.showPane", false);
user_pref("extensions.htmlaboutaddons.recommendations.enabled", false);
user_pref("browser.discovery.enabled", false);
user_pref("browser.shell.checkDefaultBrowser", false);
user_pref("browser.newtabpage.activity-stream.asrouter.userprefs.cfr.addons", false);
user_pref("browser.newtabpage.activity-stream.asrouter.userprefs.cfr.features", false);
user_pref("browser.preferences.moreFromMozilla", false);
user_pref("browser.aboutConfig.showWarning", false);
user_pref("browser.startup.homepage_override.mstone", "ignore");
user_pref("browser.aboutwelcome.enabled", false);
user_pref("browser.profiles.enabled", true);

/** THEME ADJUSTMENTS ***/
user_pref("toolkit.legacyUserProfileCustomizations.stylesheets", true);
user_pref("browser.compactmode.show", true);
user_pref("browser.privateWindowSeparation.enabled", false); // WINDOWS

/** AI ***/
user_pref("browser.ml.enable", false);
user_pref("browser.ml.chat.enabled", false);
user_pref("browser.ml.chat.menu", false);
user_pref("browser.tabs.groups.smart.enabled", false);
user_pref("browser.ml.linkPreview.enabled", false);

/** FULLSCREEN NOTICE ***/
user_pref("full-screen-api.transition-duration.enter", "0 0");
user_pref("full-screen-api.transition-duration.leave", "0 0");
user_pref("full-screen-api.warning.timeout", 0);

/** URL BAR ***/
user_pref("browser.urlbar.trending.featureGate", false);

/** NEW TAB PAGE ***/
user_pref("browser.newtabpage.activity-stream.default.sites", "");
user_pref("browser.newtabpage.activity-stream.showSponsoredTopSites", false);
user_pref("browser.newtabpage.activity-stream.feeds.section.topstories", false);
user_pref("browser.newtabpage.activity-stream.showSponsored", false);
user_pref("browser.newtabpage.activity-stream.showSponsoredCheckboxes", false);

/** DOWNLOADS ***/
user_pref("browser.download.manager.addToRecentDocs", false);

/** PDF ***/
user_pref("browser.download.open_pdf_attachments_inline", true);

/** TAB BEHAVIOR ***/
user_pref("browser.bookmarks.openInTabClosesMenu", false);
user_pref("browser.menu.showViewImageInfo", true);
user_pref("findbar.highlightAll", true);
user_pref("layout.word_select.eat_space_to_next_word", false);

/****************************************************************************
* START: MY OVERRIDES *
****************************************************************************/
// visit https://github.com/yokoffing/Betterfox/wiki/Common-Overrides
// visit https://github.com/yokoffing/Betterfox/wiki/Optional-Hardening
// Enter your personal overrides below this line:
// PREF: restore Top Sites on New Tab page
user_pref("browser.newtabpage.activity-stream.feeds.topsites", true); // Shortcuts
user_pref("browser.newtabpage.activity-stream.default.sites", ""); // clear default topsites
// This does not block you from adding your own.
user_pref("browser.newtabpage.activity-stream.default.sites", "");
// PREF: remove sponsored content on New Tab page
user_pref("browser.newtabpage.activity-stream.showSponsoredTopSites", false); // Sponsored shortcuts
user_pref("browser.newtabpage.activity-stream.feeds.section.topstories", false); // Recommended by Pocket
user_pref("browser.newtabpage.activity-stream.showSponsored", false); // Sponsored Stories
// PREF: restore search engine suggestions
user_pref("browser.search.suggest.enabled", true);
// PREF: allow websites to ask you for your location
user_pref("permissions.default.geo", 0);
// PREF: allow websites to ask you to receive site notifications
user_pref("permissions.default.desktop-notification", 0);
// PREF: improve font rendering by using DirectWrite everywhere like Chrome [WINDOWS]
user_pref("gfx.font_rendering.cleartype_params.rendering_mode", 5);
user_pref("gfx.font_rendering.cleartype_params.cleartype_level", 100);
user_pref("gfx.font_rendering.directwrite.use_gdi_table_loading", false);
user_pref("gfx.font_rendering.cleartype_params.enhanced_contrast", 50); // 50-100 [OPTIONAL]
/****************************************************************************
* SECTION: SMOOTHFOX *
****************************************************************************/
// visit https://github.com/yokoffing/Betterfox/blob/main/Smoothfox.js
// Enter your scrolling overrides below this line:
/****************************************************************************************
* OPTION: INSTANT SCROLLING (SIMPLE ADJUSTMENT) *
****************************************************************************************/
// recommended for 60hz+ displays
user_pref("apz.overscroll.enabled", true); // DEFAULT NON-LINUX
user_pref("general.smoothScroll", true); // DEFAULT
user_pref("mousewheel.default.delta_multiplier_y", 275); // 250-400; adjust this number to your liking
// Firefox Nightly only:
// [1] https://bugzilla.mozilla.org/show_bug.cgi?id=1846935
user_pref("general.smoothScroll.msdPhysics.enabled", false); // [FF122+ Nightly]
/****************************************************************************
* END: BETTERFOX *
****************************************************************************/

/*userchrome related*/
user_pref("userChrome.tab.connect_to_window", true); // Original, Photon
user_pref("userChrome.tab.color_like_toolbar", true); // Original, Photon

user_pref("userChrome.tab.lepton_like_padding", true); // Original
user_pref("userChrome.tab.photon_like_padding", false); // Photon

user_pref("userChrome.tab.dynamic_separator", true); // Original, Proton
user_pref("userChrome.tab.static_separator", false); // Photon
user_pref("userChrome.tab.static_separator.selected_accent", false); // Just option

user_pref("userChrome.tab.newtab_button_like_tab", true); // Original
user_pref("userChrome.tab.newtab_button_smaller", false); // Photon
user_pref("userChrome.tab.newtab_button_proton", false); // Proton

user_pref("userChrome.icon.panel_full", true); // Original, Proton
user_pref("userChrome.icon.panel_photon", false); // Photon
user_pref("userChrome.icon.panel_sparse", false); // Just option

// Original Only
user_pref("userChrome.tab.box_shadow", true);
user_pref("userChrome.tab.bottom_rounded_corner", true);

// Photon Only
user_pref("userChrome.tab.photon_like_contextline", false);
user_pref("userChrome.rounding.square_tab", false);

user_pref("userChrome.theme.system_default", true);
user_pref("userContent.page.illustration", true);
user_pref("userContent.page.proton_color", true);
user_pref("userContent.page.proton", true);
user_pref("userContent.page.dark_mode", true);
user_pref("userContent.page.proton_color.system_accent", true);

```

### Additional context

_No response_

The issue names no repository files, tests, or entry points. Reproduce the behavior with the listed preferences on addons.mozilla.org, support.mozilla.org, and accounts.firefox.com, then trace the theme styles affecting those pages; done means the pages follow the system dark theme.

Written by the indexing model from the issue text.