diff --git a/include/modules/battery.hpp b/include/modules/battery.hpp
index 017b0e48..1b82808c 100644
--- a/include/modules/battery.hpp
+++ b/include/modules/battery.hpp
@@ -1,45 +1,32 @@
 #pragma once
 
-#ifdef FILESYSTEM_EXPERIMENTAL
-#include <experimental/filesystem>
-#else
 #include <filesystem>
-#endif
-#include <fmt/format.h>
 #if defined(__linux__)
 #include <sys/inotify.h>
 #endif
 
-#include <algorithm>
-#include <fstream>
-#include <string>
-#include <vector>
-
 #include "ALabel.hpp"
 #include "util/sleeper_thread.hpp"
 
 namespace waybar::modules {
 
-#ifdef FILESYSTEM_EXPERIMENTAL
-namespace fs = std::experimental::filesystem;
-#else
 namespace fs = std::filesystem;
-#endif
 
-class Battery : public ALabel {
+class Battery final : public ALabel {
  public:
   Battery(const std::string&, const Json::Value&);
   virtual ~Battery();
   auto update() -> void override;
 
  private:
-  static inline const fs::path data_dir_ = "/sys/class/power_supply/";
+  static inline const fs::path data_dir_{"/sys/class/power_supply/"};
 
   void refreshBatteries();
   void worker();
   const std::string getAdapterStatus(uint8_t capacity) const;
   const std::tuple<uint8_t, float, std::string, float> getInfos();
   const std::string formatTimeRemaining(float hoursRemaining);
+  void setBarClass(std::string&);
 
   int global_watch;
   std::map<fs::path, int> batteries_;
diff --git a/include/modules/systemd_failed_units.hpp b/include/modules/systemd_failed_units.hpp
index 7e0b1a91..d305264d 100644
--- a/include/modules/systemd_failed_units.hpp
+++ b/include/modules/systemd_failed_units.hpp
@@ -1,15 +1,16 @@
 #pragma once
 
-#include <string>
 #include <giomm/dbusproxy.h>
 
+#include <string>
+
 #include "ALabel.hpp"
 
 namespace waybar::modules {
 
 class SystemdFailedUnits : public ALabel {
  public:
-  SystemdFailedUnits(const std::string&, const Json::Value&);
+  SystemdFailedUnits(const std::string &, const Json::Value &);
   virtual ~SystemdFailedUnits();
   auto update() -> void override;
 
diff --git a/man/waybar-battery.5.scd b/man/waybar-battery.5.scd
index 7827f4a8..52a6a2d1 100644
--- a/man/waybar-battery.5.scd
+++ b/man/waybar-battery.5.scd
@@ -167,3 +167,10 @@ The *battery* module allows one to define custom formats based on up to two fact
 	- *<state>* can be defined in the *config*. For more information see *states*.
 - *#battery.<status>.<state>*
 	- Combination of both *<status>* and *<state>*.
+
+The following classes are applied to the entire Waybar rather than just the
+battery widget:
+
+- *window#waybar.battery-<state>*
+	- *<state>* can be defined in the *config*, as previously mentioned.
+
diff --git a/meson.build b/meson.build
index a9d16df6..9f72116f 100644
--- a/meson.build
+++ b/meson.build
@@ -22,8 +22,6 @@ endif
 
 if compiler.has_link_argument('-lc++fs')
     cpp_link_args += ['-lc++fs']
-elif compiler.has_link_argument('-lc++experimental')
-    cpp_link_args += ['-lc++experimental']
 elif compiler.has_link_argument('-lstdc++fs')
     cpp_link_args += ['-lstdc++fs']
 endif
@@ -44,15 +42,6 @@ else
     endif
 endif
 
-if not compiler.has_header('filesystem')
-    if compiler.has_header('experimental/filesystem')
-        add_project_arguments('-DFILESYSTEM_EXPERIMENTAL', language: 'cpp')
-    else
-        add_project_arguments('-DNO_FILESYSTEM', language: 'cpp')
-        warning('No filesystem header found, some modules may not work')
-    endif
-endif
-
 code = '''
 #include <langinfo.h>
 #include <locale.h>
@@ -194,6 +183,17 @@ if cava.found()
 endif
 
 inc_dirs = ['include']
+
+if is_linux
+   src_files += files('src/modules/battery.cpp')
+   man_files += files('man/waybar-battery.5.scd')
+endif
+
+if is_freebsd
+   src_files += files('src/modules/battery.cpp')
+   man_files += files('man/waybar-battery.5.scd')
+endif
+
 subdir('protocol')
 
 executable(
diff --git a/src/bar.cpp b/src/bar.cpp
index 6e7de108..6ce0f8ee 100644
--- a/src/bar.cpp
+++ b/src/bar.cpp
@@ -535,7 +535,7 @@ auto waybar::Bar::setupWidgets() -> void {
   for (auto const& module : modules_center_) {
     center_.prepend(*module);
   }
-  std::reverse(modules_right_.begin(), modules_right_.end());
+//  std::reverse(modules_right_.begin(), modules_right_.end());
   for (auto const& module : modules_right_) {
     right_.append(*module);
   }
diff --git a/src/factory.cpp b/src/factory.cpp
index 2505204a..ac5f5de6 100644
--- a/src/factory.cpp
+++ b/src/factory.cpp
@@ -116,12 +116,12 @@ waybar::AModule* waybar::Factory::makeModule(const std::string& name,
     auto hash_pos = name.find('#');
     auto ref = name.substr(0, hash_pos);
     auto id = hash_pos != std::string::npos ? name.substr(hash_pos + 1) : "";
-/* gtk4 todo
-#if defined(__FreeBSD__) || (defined(__linux__) && !defined(NO_FILESYSTEM))
+#if defined(__FreeBSD__) || defined(__linux__)
     if (ref == "battery") {
       return new waybar::modules::Battery(id, config_[name]);
     }
 #endif
+/* gtk4 todo
 #ifdef HAVE_GAMEMODE
     if (ref == "gamemode") {
       return new waybar::modules::Gamemode(id, config_[name]);
diff --git a/src/modules/battery.cpp b/src/modules/battery.cpp
index 70268c8a..3296dfb7 100644
--- a/src/modules/battery.cpp
+++ b/src/modules/battery.cpp
@@ -1,10 +1,12 @@
 #include "modules/battery.hpp"
+
+#include <fstream>
+#include <spdlog/spdlog.h>
+
 #if defined(__FreeBSD__)
 #include <sys/sysctl.h>
 #endif
-#include <spdlog/spdlog.h>
 
-#include <iostream>
 waybar::modules::Battery::Battery(const std::string& id, const Json::Value& config)
     : ALabel(config, "battery", id, "{capacity}%", 60) {
 #if defined(__linux__)
@@ -627,7 +629,7 @@ const std::string waybar::modules::Battery::formatTimeRemaining(float hoursRemai
 auto waybar::modules::Battery::update() -> void {
 #if defined(__linux__)
   if (batteries_.empty()) {
-    event_box_.hide();
+    Gtk::Label::hide();
     return;
   }
 #endif
@@ -641,6 +643,7 @@ auto waybar::modules::Battery::update() -> void {
                  [](char ch) { return ch == ' ' ? '-' : std::tolower(ch); });
   auto format = format_;
   auto state = getState(capacity, true);
+  setBarClass(state);
   auto time_remaining_formatted = formatTimeRemaining(time_remaining);
   if (tooltipEnabled()) {
     std::string tooltip_text_default;
@@ -660,15 +663,15 @@ auto waybar::modules::Battery::update() -> void {
     } else if (config_["tooltip-format"].isString()) {
       tooltip_format = config_["tooltip-format"].asString();
     }
-    label_.set_tooltip_text(fmt::format(fmt::runtime(tooltip_format),
+    Gtk::Label::set_tooltip_text(fmt::format(fmt::runtime(tooltip_format),
                                         fmt::arg("timeTo", tooltip_text_default),
                                         fmt::arg("power", power), fmt::arg("capacity", capacity),
                                         fmt::arg("time", time_remaining_formatted)));
   }
   if (!old_status_.empty()) {
-    label_.get_style_context()->remove_class(old_status_);
+    Gtk::Label::get_style_context()->remove_class(old_status_);
   }
-  label_.get_style_context()->add_class(status);
+  Gtk::Label::get_style_context()->add_class(status);
   old_status_ = status;
   if (!state.empty() && config_["format-" + status + "-" + state].isString()) {
     format = config_["format-" + status + "-" + state].asString();
@@ -678,14 +681,50 @@ auto waybar::modules::Battery::update() -> void {
     format = config_["format-" + state].asString();
   }
   if (format.empty()) {
-    event_box_.hide();
+    Gtk::Label::hide();
   } else {
-    event_box_.show();
+    Gtk::Label::show();
     auto icons = std::vector<std::string>{status + "-" + state, status, state};
-    label_.set_markup(fmt::format(
+    Gtk::Label::set_markup(fmt::format(
         fmt::runtime(format), fmt::arg("capacity", capacity), fmt::arg("power", power),
         fmt::arg("icon", getIcon(capacity, icons)), fmt::arg("time", time_remaining_formatted)));
   }
   // Call parent update
   ALabel::update();
 }
+
+void waybar::modules::Battery::setBarClass(std::string& state) {
+  // Drop style
+  auto classes = Gtk::Widget::get_css_classes();
+  const Glib::ustring prefix{"battery-"};
+
+  auto old_class_it = std::find_if(classes.cbegin(), classes.cend(), [&prefix](auto classname) {
+    return classname.rfind(prefix, 0) == 0;
+  });
+
+  auto new_class = prefix + state;
+
+  // If the bar doesn't have any `battery-` class
+  if (old_class_it == classes.end()) {
+    if (!state.empty()) {
+      Gtk::Label::get_style_context()->add_class(new_class);
+    }
+    return;
+  }
+
+  auto old_class = *old_class_it;
+
+  // If the bar has a `battery-` class,
+  // but `state` is empty
+  if (state.empty()) {
+    Gtk::Label::get_style_context()->remove_class(old_class);
+    return;
+  }
+
+  // If the bar has a `battery-` class,
+  // and `state` is NOT empty
+  if (old_class != new_class) {
+    Gtk::Label::get_style_context()->remove_class(old_class);
+    Gtk::Label::get_style_context()->add_class(new_class);
+  }
+}
diff --git a/src/modules/systemd_failed_units.cpp b/src/modules/systemd_failed_units.cpp
index 382eea4a..56e624cf 100644
--- a/src/modules/systemd_failed_units.cpp
+++ b/src/modules/systemd_failed_units.cpp
@@ -1,10 +1,11 @@
 #include "modules/systemd_failed_units.hpp"
 
-#include <cstdint>
 #include <giomm/dbusproxy.h>
 #include <glibmm/variant.h>
 #include <spdlog/spdlog.h>
 
+#include <cstdint>
+
 static const unsigned UPDATE_DEBOUNCE_TIME_MS = 1000;
 
 namespace waybar::modules {
@@ -55,23 +56,21 @@ SystemdFailedUnits::~SystemdFailedUnits() {
   if (user_proxy) user_proxy.reset();
 }
 
-auto SystemdFailedUnits::notify_cb(
-    const Glib::ustring &sender_name,
-    const Glib::ustring &signal_name,
-    const Glib::VariantContainerBase &arguments) -> void {
+auto SystemdFailedUnits::notify_cb(const Glib::ustring& sender_name,
+                                   const Glib::ustring& signal_name,
+                                   const Glib::VariantContainerBase& arguments) -> void {
   if (signal_name == "PropertiesChanged" && !update_pending) {
     update_pending = true;
     /* The fail count may fluctuate due to restarting. */
-    Glib::signal_timeout().connect_once(
-        sigc::mem_fun(*this, &SystemdFailedUnits::updateData),
-        UPDATE_DEBOUNCE_TIME_MS);
+    Glib::signal_timeout().connect_once(sigc::mem_fun(*this, &SystemdFailedUnits::updateData),
+                                        UPDATE_DEBOUNCE_TIME_MS);
   }
 }
 
 void SystemdFailedUnits::updateData() {
   update_pending = false;
 
-  auto load = [](const char* kind, Glib::RefPtr<Gio::DBus::Proxy> &proxy) -> uint32_t {
+  auto load = [](const char* kind, Glib::RefPtr<Gio::DBus::Proxy>& proxy) -> uint32_t {
     try {
       auto parameters = Glib::VariantContainerBase(
           g_variant_new("(ss)", "org.freedesktop.systemd1.Manager", "NFailedUnits"));
@@ -123,11 +122,9 @@ auto SystemdFailedUnits::update() -> void {
   last_status = status;
 
   label_.set_markup(fmt::format(
-      fmt::runtime(nr_failed == 0 ? format_ok : format_),
-      fmt::arg("nr_failed", nr_failed),
-      fmt::arg("nr_failed_system", nr_failed_system),
-      fmt::arg("nr_failed_user", nr_failed_user)));
+      fmt::runtime(nr_failed == 0 ? format_ok : format_), fmt::arg("nr_failed", nr_failed),
+      fmt::arg("nr_failed_system", nr_failed_system), fmt::arg("nr_failed_user", nr_failed_user)));
   ALabel::update();
 }
 
-} // namespace waybar::modules::systemd_failed_units
+}  // namespace waybar::modules