diff --git a/libs/vtextedit b/libs/vtextedit
index 01fb4118..5fe5d4be 160000
--- a/libs/vtextedit
+++ b/libs/vtextedit
@@ -1 +1 @@
-Subproject commit 01fb4118f566ff7a71db67af72de1d586a0e9ee5
+Subproject commit 5fe5d4be7191de58fd1c2411b1ff97bcbecfaa3d
diff --git a/src/core/buffer/buffer.cpp b/src/core/buffer/buffer.cpp
index 283a62b4..ba4fe47a 100644
--- a/src/core/buffer/buffer.cpp
+++ b/src/core/buffer/buffer.cpp
@@ -212,7 +212,7 @@ Buffer::OperationCode Buffer::save(bool p_force)
         try {
             m_provider->write(m_content);
         } catch (Exception &p_e) {
-            qWarning() << "failed to write the buffer content" << getPath();
+            qWarning() << "failed to write the buffer content" << getPath() << p_e.what();
             return OperationCode::Failed;
         }
 
@@ -327,7 +327,7 @@ void Buffer::autoSave()
         try {
             writeBackupFile();
         } catch (Exception &p_e) {
-            qWarning() << "AutoSave failed to write backup file, retry later";
+            qWarning() << "AutoSave failed to write backup file, retry later" << p_e.what();
         }
         break;
     }
diff --git a/src/core/configmgr.cpp b/src/core/configmgr.cpp
index f042c3e1..1fcad027 100644
--- a/src/core/configmgr.cpp
+++ b/src/core/configmgr.cpp
@@ -24,7 +24,7 @@
 using namespace vnotex;
 
 #ifndef QT_NO_DEBUG
-#define VX_DEBUG_WEB
+// #define VX_DEBUG_WEB
 #endif
 
 const QString ConfigMgr::c_orgName = "VNote";
diff --git a/src/core/htmltemplatehelper.cpp b/src/core/htmltemplatehelper.cpp
index 5a5ec44e..f1edc831 100644
--- a/src/core/htmltemplatehelper.cpp
+++ b/src/core/htmltemplatehelper.cpp
@@ -24,6 +24,7 @@ QString WebGlobalOptions::toJavascriptObject() const
            + QString("htmlTagEnabled: %1,\n").arg(Utils::boolToString(m_htmlTagEnabled))
            + QString("autoBreakEnabled: %1,\n").arg(Utils::boolToString(m_autoBreakEnabled))
            + QString("linkifyEnabled: %1,\n").arg(Utils::boolToString(m_linkifyEnabled))
+           + QString("indentFirstLineEnabled: %1,\n").arg(Utils::boolToString(m_indentFirstLineEnabled))
            + QString("sectionNumberEnabled: %1\n").arg(Utils::boolToString(m_sectionNumberEnabled))
            + QStringLiteral("}");
 }
@@ -161,6 +162,7 @@ void HtmlTemplateHelper::updateMarkdownViewerTemplate(const MarkdownEditorConfig
         opts.m_htmlTagEnabled = p_config.getHtmlTagEnabled();
         opts.m_autoBreakEnabled = p_config.getAutoBreakEnabled();
         opts.m_linkifyEnabled = p_config.getLinkifyEnabled();
+        opts.m_indentFirstLineEnabled = p_config.getIndentFirstLineEnabled();
         fillGlobalOptions(s_markdownViewerTemplate.m_template, opts);
     }
 
diff --git a/src/core/htmltemplatehelper.h b/src/core/htmltemplatehelper.h
index ded17b4d..a421edbc 100644
--- a/src/core/htmltemplatehelper.h
+++ b/src/core/htmltemplatehelper.h
@@ -26,6 +26,8 @@ namespace vnotex
 
         bool m_linkifyEnabled = true;
 
+        bool m_indentFirstLineEnabled = false;
+
         QString toJavascriptObject() const;
     };
 
diff --git a/src/core/mainconfig.cpp b/src/core/mainconfig.cpp
index 1451be95..3bfcabc3 100644
--- a/src/core/mainconfig.cpp
+++ b/src/core/mainconfig.cpp
@@ -117,5 +117,4 @@ QString MainConfig::getVersion(const QJsonObject &p_jobj)
 void MainConfig::doVersionSpecificOverride()
 {
     // In a new version, we may want to change one value by force.
-    m_coreConfig->setTheme(QStringLiteral("moonlight"));
 }
diff --git a/src/core/markdowneditorconfig.cpp b/src/core/markdowneditorconfig.cpp
index 51562513..4ef0fcda 100644
--- a/src/core/markdowneditorconfig.cpp
+++ b/src/core/markdowneditorconfig.cpp
@@ -46,6 +46,7 @@ void MarkdownEditorConfig::init(const QJsonObject &p_app, const QJsonObject &p_u
     m_htmlTagEnabled = READBOOL(QStringLiteral("html_tag"));
     m_autoBreakEnabled = READBOOL(QStringLiteral("auto_break"));
     m_linkifyEnabled = READBOOL(QStringLiteral("linkify"));
+    m_indentFirstLineEnabled = READBOOL(QStringLiteral("indent_first_line"));
 }
 
 QJsonObject MarkdownEditorConfig::toJson() const
@@ -69,6 +70,7 @@ QJsonObject MarkdownEditorConfig::toJson() const
     obj[QStringLiteral("html_tag")] = m_htmlTagEnabled;
     obj[QStringLiteral("auto_break")] = m_autoBreakEnabled;
     obj[QStringLiteral("linkify")] = m_linkifyEnabled;
+    obj[QStringLiteral("indent_first_line")] = m_indentFirstLineEnabled;
     return obj;
 }
 
@@ -229,6 +231,16 @@ void MarkdownEditorConfig::setLinkifyEnabled(bool p_enabled)
     updateConfig(m_linkifyEnabled, p_enabled, this);
 }
 
+bool MarkdownEditorConfig::getIndentFirstLineEnabled() const
+{
+    return m_indentFirstLineEnabled;
+}
+
+void MarkdownEditorConfig::setIndentFirstLineEnabled(bool p_enabled)
+{
+    updateConfig(m_indentFirstLineEnabled, p_enabled, this);
+}
+
 QString MarkdownEditorConfig::sectionNumberModeToString(SectionNumberMode p_mode) const
 {
     switch (p_mode) {
diff --git a/src/core/markdowneditorconfig.h b/src/core/markdowneditorconfig.h
index 28525b00..c0473bbf 100644
--- a/src/core/markdowneditorconfig.h
+++ b/src/core/markdowneditorconfig.h
@@ -81,6 +81,9 @@ namespace vnotex
         bool getLinkifyEnabled() const;
         void setLinkifyEnabled(bool p_enabled);
 
+        bool getIndentFirstLineEnabled() const;
+        void setIndentFirstLineEnabled(bool p_enabled);
+
     private:
         QString sectionNumberModeToString(SectionNumberMode p_mode) const;
         SectionNumberMode stringToSectionNumberMode(const QString &p_str) const;
@@ -131,6 +134,9 @@ namespace vnotex
 
         // Whether convert URL-like text to links.
         bool m_linkifyEnabled = true;
+
+        // Whether indent the first line of a paragraph.
+        bool m_indentFirstLineEnabled = false;
     };
 }
 
diff --git a/src/data/core/Info.plist b/src/data/core/Info.plist
index 89b9899a..9eeb37d1 100644
--- a/src/data/core/Info.plist
+++ b/src/data/core/Info.plist
@@ -2,6 +2,22 @@
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
+    <key>CFBundleDocumentTypes</key>
+    <array>
+        <dict>
+            <key>CFBundleTypeIconFile</key>
+            <string>vnote.icns</string>
+            <key>CFBundleTypeName</key>
+            <string>VNote Document</string>
+            <key>CFBundleTypeRole</key>
+            <string>Editor</string>
+            <key>LSItemContentTypes</key>
+            <array>
+                <string>public.plain-text</string>
+                <string>net.daringfireball.markdown</string>
+            </array>
+        </dict>
+    </array>
     <key>CFBundleExecutable</key>
     <string>vnote</string>
     <key>CFBundleShortVersionString</key>
diff --git a/src/data/core/vnotex.json b/src/data/core/vnotex.json
index 1e0699fb..c285437f 100644
--- a/src/data/core/vnotex.json
+++ b/src/data/core/vnotex.json
@@ -245,7 +245,9 @@
             "//comment" : "Whether auto break a line with '\\n'",
             "auto_break" : false,
             "//comment" : "Whether convert URL-like text to links",
-            "linkify" : true
+            "linkify" : true,
+            "//comment" : "Whether add indentation to the first line of paragraph",
+            "indent_first_line" : false
         }
     },
     "widget" : {
diff --git a/src/data/extra/themes/moonlight/interface.qss b/src/data/extra/themes/moonlight/interface.qss
index 5f155684..fa2cb54f 100644
--- a/src/data/extra/themes/moonlight/interface.qss
+++ b/src/data/extra/themes/moonlight/interface.qss
@@ -897,6 +897,11 @@ QAbstractSpinBox {
     selection-background-color: @widgets#qspinbox#selection#bg;
 }
 
+QAbstractSpinBox:disabled {
+    color: @widgets#qspinbox#disabled#fg;
+    background-color: @widgets#qspinbox#disabled#bg;
+}
+
 QAbstractSpinBox:focus {
     border: 2px solid @widgets#qspinbox#focus#border;
     background-color: @widgets#qspinbox#focus#bg;
diff --git a/src/data/extra/themes/moonlight/palette.json b/src/data/extra/themes/moonlight/palette.json
index 8124605b..9e9f83c1 100644
--- a/src/data/extra/themes/moonlight/palette.json
+++ b/src/data/extra/themes/moonlight/palette.json
@@ -516,6 +516,10 @@
             "border" : "@base#content#border",
             "fg" : "@base#content#fg",
             "bg" : "@base#content#bg",
+            "disabled" : {
+                "fg" : "@base#content#disabled#fg",
+                "bg" : "@base#content#disabled#bg"
+            },
             "selection" : {
                 "fg" : "@base#content#selection#fg",
                 "bg" : "@base#content#selection#bg"
diff --git a/src/data/extra/web/css/globalstyles.css b/src/data/extra/web/css/globalstyles.css
index 429bbe96..9733b67f 100644
--- a/src/data/extra/web/css/globalstyles.css
+++ b/src/data/extra/web/css/globalstyles.css
@@ -81,3 +81,7 @@
     visibility: visible;
     vertical-align: middle;
 }
+
+#vx-content.vx-indent-first-line p {
+    text-indent: 2em;
+}
diff --git a/src/data/extra/web/js/markdownit.js b/src/data/extra/web/js/markdownit.js
index 3b07b546..665b722a 100644
--- a/src/data/extra/web/js/markdownit.js
+++ b/src/data/extra/web/js/markdownit.js
@@ -240,6 +240,10 @@ class MarkdownIt extends VxWorker {
     }
 
     registerInternal() {
+        this.vnotex.on('ready', () => {
+            this.setConstrainImageWidthEnabled(window.vxOptions.constrainImageWidthEnabled);
+            this.setIndentFirstLineEnabled(window.vxOptions.indentFirstLineEnabled);
+        });
         this.vnotex.on('markdownTextUpdated', (p_text) => {
             this.render(this.vnotex.contentContainer,
                         p_text,
@@ -247,6 +251,24 @@ class MarkdownIt extends VxWorker {
         });
     }
 
+    setConstrainImageWidthEnabled(p_enabled) {
+        let constrainClass = 'vx-constrain-image-width';
+        if (p_enabled) {
+            this.vnotex.contentContainer.classList.add(constrainClass);
+        } else {
+            this.vnotex.contentContainer.classList.remove(constrainClass);
+        }
+    }
+
+    setIndentFirstLineEnabled(p_enabled) {
+        let constrainClass = 'vx-indent-first-line';
+        if (p_enabled) {
+            this.vnotex.contentContainer.classList.add(constrainClass);
+        } else {
+            this.vnotex.contentContainer.classList.remove(constrainClass);
+        }
+    }
+
     // Render Markdown @p_text to HTML in @p_node.
     // @p_finishCbStr will be called after finishing loading new content nodes.
     // This could prevent Mermaid Gantt from negative width error.
diff --git a/src/data/extra/web/js/utils.js b/src/data/extra/web/js/utils.js
index 4eaee62d..d1a15d6c 100644
--- a/src/data/extra/web/js/utils.js
+++ b/src/data/extra/web/js/utils.js
@@ -111,6 +111,6 @@ class Utils {
     }
 
     static headingSequenceRegExp() {
-        return /^\d(?:\.\d)*\.? /;
+        return /^\d{1,3}(?:\.\d+)*\.? /;
     }
 }
diff --git a/src/data/extra/web/js/vnotex.js b/src/data/extra/web/js/vnotex.js
index d9b73613..e1377498 100644
--- a/src/data/extra/web/js/vnotex.js
+++ b/src/data/extra/web/js/vnotex.js
@@ -136,7 +136,6 @@ class VNoteX extends EventEmitter {
     }
 
     setBasicMarkdownRendered() {
-        this.setConstrainImageWidthEnabled(window.vxOptions.constrainImageWidthEnabled);
         this.emit('basicMarkdownRendered');
     }
 
@@ -210,15 +209,6 @@ class VNoteX extends EventEmitter {
         }
     }
 
-    setConstrainImageWidthEnabled(p_enabled) {
-        let constrainClass = 'vx-constrain-image-width';
-        if (p_enabled) {
-            this.contentContainer.classList.add(constrainClass);
-        } else {
-            this.contentContainer.classList.remove(constrainClass);
-        }
-    }
-
     scroll(p_up) {
         EasyAccess.scroll(p_up);
     }
diff --git a/src/widgets/dialogs/dialog.cpp b/src/widgets/dialogs/dialog.cpp
index 4fc17a87..e8a93f26 100644
--- a/src/widgets/dialogs/dialog.cpp
+++ b/src/widgets/dialogs/dialog.cpp
@@ -76,6 +76,10 @@ QDialogButtonBox *Dialog::getDialogButtonBox() const
 void Dialog::setInformationText(const QString &p_text, InformationLevel p_level)
 {
     if (!m_infoTextEdit) {
+        if (p_text.isEmpty()) {
+            return;
+        }
+
         m_infoTextEdit = new QPlainTextEdit(this);
         m_infoTextEdit->setReadOnly(true);
         m_infoTextEdit->setMaximumHeight(m_infoTextEdit->minimumSizeHint().height());
@@ -83,7 +87,10 @@ void Dialog::setInformationText(const QString &p_text, InformationLevel p_level)
     }
 
     m_infoTextEdit->setPlainText(p_text);
-    m_infoTextEdit->setVisible(!p_text.isEmpty());
+
+    const bool visible = !p_text.isEmpty();
+    const bool needResize = visible != m_infoTextEdit->isVisible();
+    m_infoTextEdit->setVisible(visible);
 
     // Change the style.
     const char *level = "";
@@ -102,7 +109,9 @@ void Dialog::setInformationText(const QString &p_text, InformationLevel p_level)
     }
 
     WidgetUtils::setPropertyDynamically(m_infoTextEdit, PropertyDefs::s_state, level);
-    WidgetUtils::updateSize(this);
+    if (needResize) {
+        WidgetUtils::updateSize(this);
+    }
 }
 
 void Dialog::acceptedButtonClicked()
diff --git a/src/widgets/dialogs/settings/markdowneditorpage.cpp b/src/widgets/dialogs/settings/markdowneditorpage.cpp
index 3f0f63e7..f0c912fa 100644
--- a/src/widgets/dialogs/settings/markdowneditorpage.cpp
+++ b/src/widgets/dialogs/settings/markdowneditorpage.cpp
@@ -66,6 +66,8 @@ void MarkdownEditorPage::loadInternal()
     m_autoBreakCheckBox->setChecked(markdownConfig.getAutoBreakEnabled());
 
     m_linkifyCheckBox->setChecked(markdownConfig.getLinkifyEnabled());
+
+    m_indentFirstLineCheckBox->setChecked(markdownConfig.getIndentFirstLineEnabled());
 }
 
 void MarkdownEditorPage::saveInternal()
@@ -97,6 +99,8 @@ void MarkdownEditorPage::saveInternal()
 
     markdownConfig.setLinkifyEnabled(m_linkifyCheckBox->isChecked());
 
+    markdownConfig.setIndentFirstLineEnabled(m_indentFirstLineCheckBox->isChecked());
+
     EditorPage::notifyEditorConfigChange();
 }
 
@@ -164,6 +168,16 @@ QGroupBox *MarkdownEditorPage::setupReadGroup()
                 this, &MarkdownEditorPage::pageIsChanged);
     }
 
+    {
+        const QString label(tr("Indent first line"));
+        m_indentFirstLineCheckBox = WidgetsFactory::createCheckBox(label, box);
+        m_indentFirstLineCheckBox->setToolTip(tr("Indent the first line of each paragraph"));
+        layout->addRow(m_indentFirstLineCheckBox);
+        addSearchItem(label, m_indentFirstLineCheckBox->toolTip(), m_indentFirstLineCheckBox);
+        connect(m_indentFirstLineCheckBox, &QCheckBox::stateChanged,
+                this, &MarkdownEditorPage::pageIsChanged);
+    }
+
     return box;
 }
 
diff --git a/src/widgets/dialogs/settings/markdowneditorpage.h b/src/widgets/dialogs/settings/markdowneditorpage.h
index bf64ab36..65425198 100644
--- a/src/widgets/dialogs/settings/markdowneditorpage.h
+++ b/src/widgets/dialogs/settings/markdowneditorpage.h
@@ -47,6 +47,8 @@ namespace vnotex
 
         QCheckBox *m_linkifyCheckBox = nullptr;
 
+        QCheckBox *m_indentFirstLineCheckBox = nullptr;
+
         QDoubleSpinBox *m_zoomFactorSpinBox = nullptr;
 
         QComboBox *m_sectionNumberComboBox = nullptr;
diff --git a/src/widgets/editors/markdowneditor.h b/src/widgets/editors/markdowneditor.h
index efd81d17..f9be76ff 100644
--- a/src/widgets/editors/markdowneditor.h
+++ b/src/widgets/editors/markdowneditor.h
@@ -187,7 +187,7 @@ namespace vnotex
         QTimer *m_sectionNumberTimer = nullptr;
 
         // Used to detect the config change and do a clean up.
-        bool m_sectionNumberEnabled = true;
+        bool m_sectionNumberEnabled = false;
 
         OverrideState m_overriddenSectionNumber = OverrideState::NoOverride;
     };
diff --git a/src/widgets/markdownviewwindow.cpp b/src/widgets/markdownviewwindow.cpp
index 5aeeb1c4..ad253cc2 100644
--- a/src/widgets/markdownviewwindow.cpp
+++ b/src/widgets/markdownviewwindow.cpp
@@ -399,7 +399,7 @@ void MarkdownViewWindow::setupViewer()
     // Status widget.
     {
         // TODO: implement a real status widget for viewer.
-        auto label = new QLabel(tr("Markdown Web Viewer"), this);
+        auto label = new QLabel(tr("Markdown Viewer"), this);
         label->setAlignment(Qt::AlignRight | Qt::AlignVCenter);
         m_viewerStatusWidget.reset(label);
         getMainStatusWidget()->addWidget(m_viewerStatusWidget.get());