diff --git a/modmanager.pro b/modmanager.pro
index 7cd6fc9..c59b5a2 100644
--- a/modmanager.pro
+++ b/modmanager.pro
@@ -123,7 +123,6 @@ win32 {
   #native blur
   LIBS += -ldwmapi
 
-
   QMAKE_CXXFLAGS += $$system($$pkgConfigExecutable() --cflags libaria2)
   LIBS += $$system($$pkgConfigExecutable() --libs libaria2 | sed 's/\/lib\b/\/bin/' | sed 's/-laria2/-laria2-0/')
   equals(QT_MAJOR_VERSION, 5){
diff --git a/src/gameversion.cpp b/src/gameversion.cpp
index 2397ca3..22e0aaa 100644
--- a/src/gameversion.cpp
+++ b/src/gameversion.cpp
@@ -8,8 +8,6 @@
 
 #include "curseforge/curseforgeapi.h"
 #include "util/tutil.hpp"
-#include "util/funcutil.h"
-#include "config.hpp"
 
 GameVersion GameVersion::Any = GameVersion("");
 
@@ -17,6 +15,7 @@ QList<GameVersion> GameVersion::mojangVersionList_;
 QList<GameVersion> GameVersion::curseforgeVersionList_;
 
 QList<GameVersion> GameVersion::cachedVersionList_{
+    GameVersion(1, 21),
     GameVersion(1, 20, 6),
     GameVersion(1, 20, 5),
     GameVersion(1, 20, 4),
diff --git a/src/qss/stylesheets.cpp b/src/qss/stylesheets.cpp
index 5f2f58e..ec0519e 100644
--- a/src/qss/stylesheets.cpp
+++ b/src/qss/stylesheets.cpp
@@ -36,20 +36,34 @@ QMap<QString, QString> styleSheets()
     return styleSheets;
 }
 
-QString styleSheetPath(const QString &name)
+QString styleSheetPath(QString name)
 {
-    if(!styleSheets().contains(name))
-        return QString("file:///:/stylesheet/%1.qss").arg("basic");
-    auto fileName = QDir(styleSheetsPath()).absoluteFilePath(name + ".qss");
-    if(!QFileInfo::exists(fileName) && builtinStyleSheets().contains(name)){
-        QFile builtinFile(QString(":/stylesheet/%1.qss").arg(name));
-        QFile newFile(fileName);
-        if(builtinFile.open(QIODevice::ReadOnly) && newFile.open(QIODevice::WriteOnly)){
-            newFile.write("/* This file is auto generated from built-in stylesheet\n"
-                          " * you can create you own qss based on this file.\n"
-                          " */\n\n");
-            newFile.write(builtinFile.readAll());
-        }
+    if(!styleSheets().keys().contains(name))
+        name = "basic";
+    if(builtinStyleSheets().keys().contains(name)){
+        QFile f(QString(":/stylesheet/%1.qss").arg(name));
+        if(f.open(QIODevice::ReadOnly))
+            return f.readAll();
     }
+    auto fileName = QDir(styleSheetsPath()).absoluteFilePath(name + ".qss");
     return fileName.prepend("file:///");
 }
+
+QString copyStyleSheet(const QString &name)
+{
+    QFile oldFile;
+    if(builtinStyleSheets().keys().contains(name))
+        oldFile.setFileName(QString(":/stylesheet/%1.qss").arg(name));
+    else
+        oldFile.setFileName(QString("file:///:/stylesheet/%1.qss").arg(name));
+    auto newName = name+"-copy";
+    auto fileName = QDir(styleSheetsPath()).absoluteFilePath(newName + ".qss");
+    QFile newFile(fileName);
+    if(!newFile.exists() && oldFile.open(QIODevice::ReadOnly) && newFile.open(QIODevice::WriteOnly)){
+        newFile.write("/* This file is auto generated from existed stylesheet\n"
+                      " * you can create you own qss based on this file.\n"
+                      " */\n\n");
+        newFile.write(oldFile.readAll());
+    }
+    return newName;
+}
diff --git a/src/qss/stylesheets.h b/src/qss/stylesheets.h
index 9496feb..591c8bf 100644
--- a/src/qss/stylesheets.h
+++ b/src/qss/stylesheets.h
@@ -7,5 +7,6 @@ const QString &styleSheetsPath();
 const QMap<QString, QString> &builtinStyleSheets();
 QMap<QString, QString> styleSheets();
 
-QString styleSheetPath(const QString &name);
+QString styleSheetPath(QString name);
+QString copyStyleSheet(const QString &name);
 #endif // STYLESHEETS_H
diff --git a/src/ui/framelesswrapper.cpp b/src/ui/framelesswrapper.cpp
index fde11ad..98c1c2e 100644
--- a/src/ui/framelesswrapper.cpp
+++ b/src/ui/framelesswrapper.cpp
@@ -88,7 +88,6 @@ bool FramelessWrapper::nativeEvent(const QByteArray &eventType, void *message, l
     switch(msg->message){
     case WM_NCCALCSIZE:{
         if(msg->wParam == FALSE) return false;
-
         *result = WVR_REDRAW;
         return true;
     }
diff --git a/src/ui/modmanager.cpp b/src/ui/modmanager.cpp
index 49706d2..0a30e8f 100644
--- a/src/ui/modmanager.cpp
+++ b/src/ui/modmanager.cpp
@@ -223,7 +223,7 @@ void ModManager::paintEvent(QPaintEvent *event[[maybe_unused]])
         if(!widget->isVisible()) continue;
         auto rect = widget->rect();
         rect.translate(widget->pos());
-        p.fillRect(rect, QBrush(QColor(255, 50, 255, 210)));
+        p.fillRect(rect, QBrush(QColor(255, 255, 255, 210)));
     }
 }
 #endif //defined (DE_KDE) || defined (Q_OS_WIN)
@@ -242,11 +242,12 @@ void ModManager::editLocalPath(int index)
 void ModManager::on_actionPreferences_triggered()
 {
     auto preferences = new Preferences(this);
-    auto style = config_.getCustomStyle();
-    connect(preferences, &Preferences::accepted, this, [=]{
-        if(auto afterStyle = config_.getCustomStyle(); afterStyle != style)
-            qApp->setStyleSheet(styleSheetPath(afterStyle));
-    });
+    // TODO: mass performance
+    // auto style = config_.getCustomStyle();
+    // connect(preferences, &Preferences::accepted, this, [=]{
+    //     if(auto afterStyle = config_.getCustomStyle(); afterStyle != style)
+    //         qApp->setStyleSheet(styleSheetPath(afterStyle));
+    // });
     connect(preferences, &Preferences::accepted, this, &ModManager::updateUi, Qt::UniqueConnection);
     connect(preferences, &Preferences::accepted, this, &ModManager::setProxy, Qt::UniqueConnection);
     connect(preferences, &Preferences::accepted, QAria2::qaria2(), &QAria2::updateOptions, Qt::UniqueConnection);
diff --git a/src/ui/preferences.cpp b/src/ui/preferences.cpp
index 3666a66..aa3ad86 100644
--- a/src/ui/preferences.cpp
+++ b/src/ui/preferences.cpp
@@ -1,6 +1,7 @@
 #include "preferences.h"
 #include "ui_preferences.h"
 
+#include <QDesktopServices>
 #include <QFileDialog>
 
 #include "config.hpp"
@@ -19,8 +20,7 @@ Preferences::Preferences(QWidget *parent) :
 #endif
     auto s = styleSheets();
     for(auto it = s.cbegin(); it != s.cend(); it++){
-        ui->customStyle->addItem(it.value());
-        ui->customStyle->setItemData(ui->customStyle->count() - 1, it.key());
+        ui->customStyle->addItem(it.value(), it.key());
     }
 
     ui->language->addItem(tr("Follow System"));
@@ -186,6 +186,13 @@ void Preferences::on_proxyType_currentIndexChanged(int index)
     ui->proxyPassword->setEnabled(!noProxy);
 }
 
+void Preferences::on_copyQSSButton_clicked()
+{
+    auto name = copyStyleSheet(ui->customStyle->currentData().toString());
+    ui->customStyle->insertItem(ui->customStyle->currentIndex() + 1, name, name);
+    ui->customStyle->setCurrentText(name);
+    QDesktopServices::openUrl(QUrl(styleSheetPath(name)));
+}
 
 void Preferences::on_useFramelessWindow_toggled(bool checked[[maybe_unused]])
 {
diff --git a/src/ui/preferences.h b/src/ui/preferences.h
index cb57706..5920c15 100644
--- a/src/ui/preferences.h
+++ b/src/ui/preferences.h
@@ -22,6 +22,8 @@ private slots:
 
     void on_proxyType_currentIndexChanged(int index);
 
+    void on_copyQSSButton_clicked();
+
 private:
     Ui::Preferences *ui;
 };
diff --git a/src/ui/preferences.ui b/src/ui/preferences.ui
index a21d8cc..ce2fe02 100644
--- a/src/ui/preferences.ui
+++ b/src/ui/preferences.ui
@@ -6,8 +6,8 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>600</width>
-    <height>673</height>
+    <width>627</width>
+    <height>772</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -69,8 +69,8 @@
            <rect>
             <x>0</x>
             <y>0</y>
-            <width>560</width>
-            <height>589</height>
+            <width>599</width>
+            <height>683</height>
            </rect>
           </property>
           <layout class="QVBoxLayout" name="verticalLayout_2">
@@ -209,26 +209,13 @@
            </item>
            <item>
             <layout class="QFormLayout" name="formLayout_4">
-             <item row="1" column="1">
-              <widget class="QComboBox" name="customStyle"/>
-             </item>
-             <item row="1" column="0">
-              <widget class="QLabel" name="label_4">
-               <property name="text">
-                <string>UI style:</string>
-               </property>
-              </widget>
-             </item>
-             <item row="2" column="0">
-              <widget class="QLabel" name="label_24">
+             <item row="0" column="0">
+              <widget class="QLabel" name="label_25">
                <property name="text">
-                <string>Language:</string>
+                <string>Mod Manager update:</string>
                </property>
               </widget>
              </item>
-             <item row="2" column="1">
-              <widget class="QComboBox" name="language"/>
-             </item>
              <item row="0" column="1">
               <widget class="QComboBox" name="autoCheckModManagerUpdate">
                <item>
@@ -248,13 +235,40 @@
                </item>
               </widget>
              </item>
-             <item row="0" column="0">
-              <widget class="QLabel" name="label_25">
+             <item row="1" column="0">
+              <widget class="QLabel" name="label_4">
                <property name="text">
-                <string>Mod Manager update:</string>
+                <string>UI style:</string>
+               </property>
+              </widget>
+             </item>
+             <item row="1" column="1">
+              <layout class="QHBoxLayout" name="horizontalLayout">
+               <item>
+                <widget class="QComboBox" name="customStyle"/>
+               </item>
+               <item>
+                <widget class="QToolButton" name="copyQSSButton">
+                 <property name="text">
+                  <string>Copy</string>
+                 </property>
+                 <property name="icon">
+                  <iconset theme="edit-copy"/>
+                 </property>
+                </widget>
+               </item>
+              </layout>
+             </item>
+             <item row="2" column="0">
+              <widget class="QLabel" name="label_24">
+               <property name="text">
+                <string>Language:</string>
                </property>
               </widget>
              </item>
+             <item row="2" column="1">
+              <widget class="QComboBox" name="language"/>
+             </item>
             </layout>
            </item>
            <item>
@@ -309,8 +323,8 @@
            <rect>
             <x>0</x>
             <y>0</y>
-            <width>576</width>
-            <height>580</height>
+            <width>599</width>
+            <height>683</height>
            </rect>
           </property>
           <layout class="QVBoxLayout" name="verticalLayout">
@@ -516,8 +530,8 @@
            <rect>
             <x>0</x>
             <y>0</y>
-            <width>560</width>
-            <height>585</height>
+            <width>599</width>
+            <height>683</height>
            </rect>
           </property>
           <layout class="QVBoxLayout" name="verticalLayout_3">
@@ -834,8 +848,8 @@
            <rect>
             <x>0</x>
             <y>0</y>
-            <width>576</width>
-            <height>580</height>
+            <width>599</width>
+            <height>683</height>
            </rect>
           </property>
           <layout class="QGridLayout" name="gridLayout_11">