diff --git a/src/EditorOther/ClochurLexer.py b/src/EditorOther/ClochurLexer.py
new file mode 100644
index 0000000..1f2374c
--- /dev/null
+++ b/src/EditorOther/ClochurLexer.py
@@ -0,0 +1,161 @@
+
+import re
+from PyQt5.Qsci import QsciLexerCustom, QsciScintilla
+from PyQt5.QtGui import *
+
+
+
+class ClochurLexer(QsciLexerCustom):
+
+    def __init__(self, parent=None):
+        QsciLexerCustom.__init__(self, parent)
+        self._styles = {
+            0: 'Default',
+            1: 'Keyword',
+            2: 'Comment',
+            3: 'String',
+            4: 'Rainbow0',
+            5: 'Rainbow1',
+            6: 'Rainbow2',
+            7: 'Rainbow3',
+            8: 'Rainbow4',
+            9: 'Rainbow5',
+            10: 'Rainbow6',
+        }
+
+        for (k,v) in self._styles.items():
+            setattr(self, v, k)
+
+        self.QUOTES = ['"', "'"]
+        self.PARENTHESIS = ["[", "]"]
+
+        self.PRIMARY = ['define', 'let' , '#t', '#f', 'lambda', '@', 'cond', 'if', 'docu']
+
+        font = QFont()
+        font.setFamily(parent.font_family)
+        font.setPointSize(parent.font_size)
+        self.setDefaultFont(font)
+
+        # set indent style
+        self.setAutoIndentStyle(QsciScintilla.AiMaintain)
+
+    def language(self):
+        return "Clochur"
+
+    def description(self, style):
+        ret = "Lexer for Clochur - a S-expression-like" + \
+            "typesetting Language. %s, %s" % (style, self._styles.get(style, ''))
+        return ret
+
+    def defaultColor(self, style):
+        if style == self.Default:
+            return QColor("#000000")
+        elif style == self.Keyword:
+            return QColor("#0000ff")
+        elif style == self.Comment:
+            return QColor("#005500")
+        elif style == self.String:
+            return QColor("#ce5c00")
+        elif style == self.Rainbow0:
+            return QColor("#ff5500")
+        elif style == self.Rainbow1:
+            return QColor("#ffaa00")
+        elif style == self.Rainbow2:
+            return QColor("#dede00")
+        elif style == self.Rainbow3:
+            return QColor("#00ff00")
+        elif style == self.Rainbow4:
+            return QColor("#00aaff")
+        elif style == self.Rainbow5:
+            return QColor("#0000ff")
+        elif style == self.Rainbow6:
+            return QColor("#aa00ff")
+
+        else:
+            return QsciLexerCustom.defaultColor(self, style)
+
+
+
+
+    def styleText(self, start, end):
+        editor = self.editor()
+        if editor is None:
+            return
+
+        SCI = editor.SendScintilla
+        set_style = self.setStyling
+
+        source = ''
+        if end > editor.length():
+            end = editor.length()
+        if end > start:
+            source = bytearray(end - start)
+            SCI(QsciScintilla.SCI_GETTEXTRANGE, start, end, source)
+        if not source:
+            return
+
+
+        self.startStyling(start, 0x1f)
+        rainbow_state = 0
+
+        index = SCI(QsciScintilla.SCI_LINEFROMPOSITION, start)
+
+        for line in source.splitlines(True):
+            #print("%s, %d" % (line, rainbow_state))
+            length = len(line)
+
+            i = 0
+
+            new_state = self.Default
+
+            line_utf8 = line.decode('utf-8')
+
+            split_pattern = re.compile(r'(\s+|\\%|%|\\\[|\\\]|[[]|[]])')
+
+            line_utf8_splitted = split_pattern.split(line_utf8)
+
+            line_utf8_splitted_len_pair = [{"str": item, "len" : len(bytearray(item, "utf-8"))} for item in line_utf8_splitted]
+
+
+            #print(line_utf8_splitted_len_pair)
+
+            is_comment = False
+
+            i = 0
+            if index > 0:
+            #    pos = SCI(QsciScintilla.SCI_GETLINEENDPOSITION, index - 1)
+                rainbow_state = SCI(QsciScintilla.SCI_GETLINESTATE, index - 1)
+            #    print(rainbow_state)
+
+            for item in line_utf8_splitted_len_pair:
+
+                '''comment'''
+                if item["str"] == "%":
+                    is_comment = True
+                if is_comment == True:
+                    new_state = self.Comment # end of comment
+                elif item["str"] in self.PRIMARY: # keywords
+                    new_state = self.Keyword
+                # string
+                elif re.match(r'^["]([^"]|\\\")*["]$' ,item["str"]) or re.match(r"^[']([^']|\\\')*[']$" ,item["str"]):
+                    new_state = self.String
+                #parenthesis: rainbow mode
+                elif item["str"] == "[":
+                    new_state = getattr(self, "Rainbow" + str(rainbow_state))
+                    rainbow_state = (rainbow_state + 1) % 7
+                elif item["str"] == "]":
+                    rainbow_state = (rainbow_state - 1) % 7
+                    new_state = getattr(self, "Rainbow" + str(rainbow_state))
+                else:
+                    pass
+
+                word_length = item["len"]
+                i += word_length
+                set_style(word_length, new_state)
+
+                if new_state != self.Comment:
+                    new_state = self.Default
+
+                SCI(QsciScintilla.SCI_SETLINESTATE, index, rainbow_state)
+
+            index += 1
diff --git a/src/EditorOther/CustomQsciEditor.py b/src/EditorOther/CustomQsciEditor.py
new file mode 100644
index 0000000..a3ef02b
--- /dev/null
+++ b/src/EditorOther/CustomQsciEditor.py
@@ -0,0 +1,54 @@
+from PyQt5.QtGui import *
+from PyQt5.Qsci import QsciScintilla
+
+from EditorOther.ClochurLexer import ClochurLexer
+
+class CustomQsciEditor(QsciScintilla):
+    def __init__(self, parent=None):
+        super(CustomQsciEditor, self).__init__(parent)
+
+        self.font_family = parent.font_family
+        self.font_size = parent.font_size
+
+        self.tab_width = 4
+
+        lexer = ClochurLexer(self)
+        self.setLexer(lexer)
+
+        # Margin 0 for line numbers
+        font = QFont()
+        font.setFamily(self.font_family)
+        font.setPointSize(self.font_size)
+        fontMetrics = QFontMetrics(font)
+        self.setMarginsFont(font)
+        self.setMarginWidth(0, fontMetrics.width("00") + 6)
+        self.setMarginLineNumbers(0, True)
+        self.setMarginsBackgroundColor(QColor("#cccccc"))
+
+        # brace matching
+
+        self.setBraceMatching(QsciScintilla.SloppyBraceMatch)
+
+        # current line color
+
+        self.setCaretLineVisible(True)
+        self.setCaretLineBackgroundColor(QColor("#fdffce"))
+
+        # set word wrap
+        self.set_word_wrap()
+
+        # set encoding
+        self.SendScintilla(QsciScintilla.SCI_SETCODEPAGE, QsciScintilla.SC_CP_UTF8)
+        self.setUtf8(True)
+
+        # set Auto indent
+        self.setAutoIndent(True)
+        self.setIndentationWidth(self.tab_width)
+        self.setIndentationsUseTabs(False)
+        self.setTabWidth(4)
+        self.setBackspaceUnindents(True)
+
+    def set_word_wrap(self):
+        self.setWrapMode(QsciScintilla.WrapMode.WrapWord)
+    def set_no_word_wrap(self):
+        self.setWrapMode(QsciScintilla.WrapMode.WrapNone)
diff --git a/src/main.py b/src/main.py
index 92c86ef..1b3f5f8 100755
--- a/src/main.py
+++ b/src/main.py
@@ -3,16 +3,15 @@
 
 import json
 import os
-import re
 import sys
 from PyQt5.QtCore import *
 from PyQt5.QtGui import *
 from PyQt5 import QtWebEngineWidgets
 from PyQt5.QtWidgets import *
-from PyQt5.Qsci import QsciScintilla, QsciLexerPython, QsciLexerCustom
+from PyQt5.Qsci import QsciScintilla
 
 import qrc_resources
-from EditorOther import FindReplace
+from EditorOther import FindReplace, CustomQsciEditor
 
 filename = None
 
@@ -21,10 +20,7 @@ dirname = os.path.abspath(os.path.dirname(__file__)) #os.path.dirname('__file__'
 PDFJS = os.path.join(dirname, '../thirdparty/pdfjs/web/viewer.html')
 PDF = os.path.join(dirname, 'example.pdf')
 
-tab_width = 4
 
-font_family = 'Noto Sans Mono'
-font_size = 11
 
 '''Widget for PDF file viewer'''
 class PDFJSWidget(QtWebEngineWidgets.QWebEngineView):
@@ -33,51 +29,7 @@ class PDFJSWidget(QtWebEngineWidgets.QWebEngineView):
         self.load(QUrl.fromUserInput("file://%s?file=file://%s"  % (PDFJS, PDF)))
         print((dirname,PDFJS, PDF))
 
-class CustomQsciEditor(QsciScintilla):
 
-    def set_word_wrap(self):
-        self.setWrapMode(QsciScintilla.WrapMode.WrapWord)
-    def set_no_word_wrap(self):
-        self.setWrapMode(QsciScintilla.WrapMode.WrapNone)
-
-    def __init__(self, parent=None):
-        super(CustomQsciEditor, self).__init__(parent)
-
-        lexer = ClochurLexer(self)
-        self.setLexer(lexer)
-
-        # Margin 0 for line numbers
-        font = QFont()
-        font.setFamily(font_family)
-        font.setPointSize(font_size)
-        fontMetrics = QFontMetrics(font)
-        self.setMarginsFont(font)
-        self.setMarginWidth(0, fontMetrics.width("00") + 6)
-        self.setMarginLineNumbers(0, True)
-        self.setMarginsBackgroundColor(QColor("#cccccc"))
-
-        # brace matching
-
-        self.setBraceMatching(QsciScintilla.SloppyBraceMatch)
-
-        # current line color
-
-        self.setCaretLineVisible(True)
-        self.setCaretLineBackgroundColor(QColor("#fdffce"))
-
-        # set word wrap
-        self.set_word_wrap()
-
-        # set encoding
-        self.SendScintilla(QsciScintilla.SCI_SETCODEPAGE, QsciScintilla.SC_CP_UTF8)
-        self.setUtf8(True)
-
-        # set Auto indent
-        self.setAutoIndent(True)
-        self.setIndentationWidth(tab_width)
-        self.setIndentationsUseTabs(False)
-        self.setTabWidth(4)
-        self.setBackspaceUnindents(True)
 
 
 class Window(QMainWindow):
@@ -85,6 +37,8 @@ class Window(QMainWindow):
         super(QMainWindow, self).__init__()
         self.file = None
         self.filename = None
+        self.font_family = 'Noto Sans Mono'
+        self.font_size = 11
 
         self.tmp_folder = '/tmp'
         self.tmp_file = 'clochur_tmp.json'
@@ -97,6 +51,8 @@ class Window(QMainWindow):
         self._createEditToolBar()
         self._createFormatToolBar()
 
+        self.setWindowIcon(QIcon(':logo.svg'))
+
     def _createActions(self):
         self.new_action = QAction(QIcon(":new.svg"), "&New", self)
         self.new_action.setShortcut('Ctrl+N')
@@ -149,6 +105,7 @@ class Window(QMainWindow):
         self.convert_action = QAction(QIcon(":convert.svg"), "Con&vert", self)
 
         self.about_action = QAction("&About", self)
+        self.about_action.triggered.connect(self.about_call)       
 
         self.bold_action = QAction(QIcon(":text-bold.svg"), "&Bold", self)
         self.italic_action = QAction(QIcon(":text-italic.svg"), "&Italic", self)
@@ -306,6 +263,13 @@ class Window(QMainWindow):
 
     def select_all_call(self):
         self.editor.selectAll()
+
+    def about_call(self):
+        about_content = '''A S-expression-like typesetting language powered by SILE engine with a simple text text editor.
+http://yoxem.github.com
+(c) 2021 Yoxem Chen <yoxem.tem98@nctu.edu.tw>'''
+
+        self.about_dialog = QMessageBox.about(self, "About Clochur", about_content)
                 
 
     def _createEditToolBar(self):
@@ -396,169 +360,17 @@ class Window(QMainWindow):
 
 
 
-class ClochurLexer(QsciLexerCustom):
 
-    def __init__(self, parent=None):
-        QsciLexerCustom.__init__(self, parent)
-        self._styles = {
-            0: 'Default',
-            1: 'Keyword',
-            2: 'Comment',
-            3: 'String',
-            4: 'Rainbow0',
-            5: 'Rainbow1',
-            6: 'Rainbow2',
-            7: 'Rainbow3',
-            8: 'Rainbow4',
-            9: 'Rainbow5',
-            10: 'Rainbow6',
-        }
-
-        for (k,v) in self._styles.items():
-            setattr(self, v, k)
-
-        self.QUOTES = ['"', "'"]
-        self.PARENTHESIS = ["[", "]"]
-
-        self.PRIMARY = ['define', 'let' , '#t', '#f', 'lambda', '@', 'cond', 'if', 'docu']
-
-        font = QFont()
-        font.setFamily(font_family)
-        font.setPointSize(font_size)
-        self.setDefaultFont(font)
-
-        # set indent style
-        self.setAutoIndentStyle(QsciScintilla.AiMaintain)
-
-    def language(self):
-        return "Clochur"
-
-    def description(self, style):
-        ret = "Lexer for Clochur - a S-expression-like" + \
-            "typesetting Language. %s, %s" % (style, self._styles.get(style, ''))
-        return ret
-
-    def defaultColor(self, style):
-        if style == self.Default:
-            return QColor("#000000")
-        elif style == self.Keyword:
-            return QColor("#0000ff")
-        elif style == self.Comment:
-            return QColor("#005500")
-        elif style == self.String:
-            return QColor("#ce5c00")
-        elif style == self.Rainbow0:
-            return QColor("#ff5500")
-        elif style == self.Rainbow1:
-            return QColor("#ffaa00")
-        elif style == self.Rainbow2:
-            return QColor("#dede00")
-        elif style == self.Rainbow3:
-            return QColor("#00ff00")
-        elif style == self.Rainbow4:
-            return QColor("#00aaff")
-        elif style == self.Rainbow5:
-            return QColor("#0000ff")
-        elif style == self.Rainbow6:
-            return QColor("#aa00ff")
-
-        else:
-            return QsciLexerCustom.defaultColor(self, style)
-
-
-
-
-    def styleText(self, start, end):
-        editor = self.editor()
-        if editor is None:
-            return
-
-        SCI = editor.SendScintilla
-        set_style = self.setStyling
-
-        source = ''
-        if end > editor.length():
-            end = editor.length()
-        if end > start:
-            source = bytearray(end - start)
-            SCI(QsciScintilla.SCI_GETTEXTRANGE, start, end, source)
-        if not source:
-            return
-
-
-        self.startStyling(start, 0x1f)
-        rainbow_state = 0
-
-        index = SCI(QsciScintilla.SCI_LINEFROMPOSITION, start)
-
-        for line in source.splitlines(True):
-            #print("%s, %d" % (line, rainbow_state))
-            length = len(line)
-
-            i = 0
-
-            new_state = self.Default
-
-            line_utf8 = line.decode('utf-8')
-
-            split_pattern = re.compile(r'(\s+|\\%|%|\\\[|\\\]|[[]|[]])')
-
-            line_utf8_splitted = split_pattern.split(line_utf8)
-
-            line_utf8_splitted_len_pair = [{"str": item, "len" : len(bytearray(item, "utf-8"))} for item in line_utf8_splitted]
-
-
-            #print(line_utf8_splitted_len_pair)
-
-            is_comment = False
-
-            i = 0
-            if index > 0:
-            #    pos = SCI(QsciScintilla.SCI_GETLINEENDPOSITION, index - 1)
-                rainbow_state = SCI(QsciScintilla.SCI_GETLINESTATE, index - 1)
-            #    print(rainbow_state)
-
-            for item in line_utf8_splitted_len_pair:
-
-                '''comment'''
-                if item["str"] == "%":
-                    is_comment = True
-                if is_comment == True:
-                    new_state = self.Comment # end of comment
-                elif item["str"] in self.PRIMARY: # keywords
-                    new_state = self.Keyword
-                # string
-                elif re.match(r'^["]([^"]|\\\")*["]$' ,item["str"]) or re.match(r"^[']([^']|\\\')*[']$" ,item["str"]):
-                    new_state = self.String
-                #parenthesis: rainbow mode
-                elif item["str"] == "[":
-                    new_state = getattr(self, "Rainbow" + str(rainbow_state))
-                    rainbow_state = (rainbow_state + 1) % 7
-                elif item["str"] == "]":
-                    rainbow_state = (rainbow_state - 1) % 7
-                    new_state = getattr(self, "Rainbow" + str(rainbow_state))
-                else:
-                    pass
-
-                word_length = item["len"]
-                i += word_length
-                set_style(word_length, new_state)
-
-                if new_state != self.Comment:
-                    new_state = self.Default
-
-                SCI(QsciScintilla.SCI_SETLINESTATE, index, rainbow_state)
-
-            index += 1
 
 
 
 
 if __name__ == '__main__':
     app = QApplication([])
+    window = Window()
 
 
-    editor = CustomQsciEditor()
+    editor = CustomQsciEditor.CustomQsciEditor(window)
     editor.setMinimumWidth(200)
     #editor.resize(QSize(500, 2000))
 
@@ -579,7 +391,6 @@ if __name__ == '__main__':
     #main_layout.addWidget(pdf_viewer)
 
 
-    window = Window()
     window.editor = editor
 
     untitled_title = window.generate_untitled_title()