diff --git a/app/build.gradle b/app/build.gradle
index 2034a5b..9576352 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -11,8 +11,8 @@ android {
         applicationId "com.github.drunlin.webappbox"
         minSdkVersion 16
         targetSdkVersion 28
-        versionCode 3
-        versionName "1.2"
+        versionCode 4
+        versionName "1.3"
 
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
     }
diff --git a/app/src/main/java/com/github/drunlin/webappbox/common/Constants.kt b/app/src/main/java/com/github/drunlin/webappbox/common/Constants.kt
index 3a20d12..d2c686a 100644
--- a/app/src/main/java/com/github/drunlin/webappbox/common/Constants.kt
+++ b/app/src/main/java/com/github/drunlin/webappbox/common/Constants.kt
@@ -37,3 +37,4 @@ val PREF_FULL_SCREEN = "full_screen"
 val PREF_CLEAR_DATA = "clear_data"
 val PREF_CLEAR_CACHE = "clear_cache"
 val PREF_LAUNCH_MODE = "launch_mode"
+val PREF_TEXT_ZOOM = "text_zoom"
diff --git a/app/src/main/java/com/github/drunlin/webappbox/data/Rule.kt b/app/src/main/java/com/github/drunlin/webappbox/data/Rule.kt
index bb0ff22..ac3fe22 100644
--- a/app/src/main/java/com/github/drunlin/webappbox/data/Rule.kt
+++ b/app/src/main/java/com/github/drunlin/webappbox/data/Rule.kt
@@ -3,6 +3,7 @@ package com.github.drunlin.webappbox.data
 data class Rule(override var id: Long,
                 var pattern: URLPattern,
                 var color: Int,
+                var textZoom: Int,
                 var launchMode: LaunchMode,
                 var orientation: Orientation,
                 var fullScreen: Boolean,
diff --git a/app/src/main/java/com/github/drunlin/webappbox/fragment/PreferencesFragment.kt b/app/src/main/java/com/github/drunlin/webappbox/fragment/PreferencesFragment.kt
index d9ff826..3cb5e0e 100644
--- a/app/src/main/java/com/github/drunlin/webappbox/fragment/PreferencesFragment.kt
+++ b/app/src/main/java/com/github/drunlin/webappbox/fragment/PreferencesFragment.kt
@@ -5,6 +5,7 @@ import android.os.Bundle
 import android.support.design.widget.Snackbar
 import android.support.v7.preference.Preference
 import android.support.v7.preference.PreferenceFragmentCompat
+import android.support.v7.preference.SeekBarPreference
 import android.view.View
 import com.github.drunlin.webappbox.R
 import com.github.drunlin.webappbox.activity.FragmentActivity
@@ -35,12 +36,23 @@ class PreferencesFragment : PreferenceFragmentCompat(), UserAgentsFragment.OnCha
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
         super.onViewCreated(view, savedInstanceState)
 
+        setupTextZoomPreference()
+
         if (Build.VERSION.SDK_INT < Build.VERSION_CODES.KITKAT)
             findPreference(PREF_COLOR).isVisible = false
 
         updateUserAgentSummary()
     }
 
+    private fun setupTextZoomPreference() {
+        val preference = findPreference(PREF_TEXT_ZOOM) as SeekBarPreference
+        preference.summary = getString(R.string.text_zoom_summary, preference.value)
+        preference.setOnPreferenceChangeListener { _, value ->
+            preference.summary = getString(R.string.text_zoom_summary, value as Int)
+            true
+        }
+    }
+
     private fun updateUserAgentSummary() {
         findPreference(PREF_USER_AGENT).summary = userAgent.name
     }
diff --git a/app/src/main/java/com/github/drunlin/webappbox/fragment/RuleEditorFragment.kt b/app/src/main/java/com/github/drunlin/webappbox/fragment/RuleEditorFragment.kt
index b2a8260..db4b469 100644
--- a/app/src/main/java/com/github/drunlin/webappbox/fragment/RuleEditorFragment.kt
+++ b/app/src/main/java/com/github/drunlin/webappbox/fragment/RuleEditorFragment.kt
@@ -4,6 +4,7 @@ import android.databinding.ViewDataBinding
 import android.os.Build
 import android.os.Bundle
 import android.view.View
+import android.widget.SeekBar
 import com.github.drunlin.webappbox.BR
 import com.github.drunlin.webappbox.R
 import com.github.drunlin.webappbox.common.BUNDLE_UA
@@ -62,6 +63,16 @@ class RuleEditorFragment(id: Long?) : EditorFragment<Rule>(id),
         editor.onStateChange = { confirmMenu?.isEnabled = it }
         editor.isExisted = { v, b -> ruleManager.isExited(v, b) }
 
+        textZoomSeekBar.setOnSeekBarChangeListener(object : SeekBar.OnSeekBarChangeListener {
+            override fun onProgressChanged(seekBar: SeekBar?, progress: Int, fromUser: Boolean) = Unit
+
+            override fun onStartTrackingTouch(seekBar: SeekBar?) = Unit
+
+            override fun onStopTrackingTouch(seekBar: SeekBar) {
+                textZoomText.text = getString(R.string.text_zoom_summary, seekBar.progress)
+            }
+        })
+
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT)
             colorItem.setOnClickListener { showDialog(ColorPickerFragment(colorView.color)) }
         else
@@ -74,7 +85,7 @@ class RuleEditorFragment(id: Long?) : EditorFragment<Rule>(id),
     }
 
     private fun updateUserAgentSummary() {
-        (binding as FragmentRuleEditorBinding).userAgentItem!!.summary = userAgent?.name
+        (binding as FragmentRuleEditorBinding).userAgentItem.summary = userAgent?.name
     }
 
     override fun onConfigureView(data: Rule) {
@@ -97,13 +108,14 @@ class RuleEditorFragment(id: Long?) : EditorFragment<Rule>(id),
         val pattern = editor.value
         val regex = editor.regex
         val color = colorView.color
+        val tz = textZoomSeekBar.progress
         val lm = LaunchMode.valueOf(launchModeSpinner.value)
         val so = Orientation.valueOf(orientationSpinner.value)
         val ua = userAgent ?: data?.userAgent ?: userAgents.getOrNull(0)
         val fs = fullScreenItem.switcher.isChecked
         val js = enableJavascriptItem.switcher.isChecked
 
-        id?.run { ruleManager.update(this, pattern, regex, color, lm, so, fs, ua, js) }
-                ?: ruleManager.insert(pattern, regex, color, lm, so, fs, ua, js)
+        id?.run { ruleManager.update(this, pattern, regex, color, tz, lm, so, fs, ua, js) }
+                ?: ruleManager.insert(pattern, regex, color, tz, lm, so, fs, ua, js)
     }
 }
diff --git a/app/src/main/java/com/github/drunlin/webappbox/fragment/WebappWindowFragment.kt b/app/src/main/java/com/github/drunlin/webappbox/fragment/WebappWindowFragment.kt
index 4f2a5d8..e5e4769 100644
--- a/app/src/main/java/com/github/drunlin/webappbox/fragment/WebappWindowFragment.kt
+++ b/app/src/main/java/com/github/drunlin/webappbox/fragment/WebappWindowFragment.kt
@@ -395,6 +395,7 @@ class WebappWindowFragment() : Fragment(), DownloadListener, OnKeyListener, OnGl
 
             updateSystemUi(url)
 
+            view.settings.textZoom = rule!!.textZoom
             view.settings.userAgentString = rule!!.userAgent.value
             view.settings.javaScriptEnabled = rule!!.jsEnabled
 
diff --git a/app/src/main/java/com/github/drunlin/webappbox/model/DatabaseManager.kt b/app/src/main/java/com/github/drunlin/webappbox/model/DatabaseManager.kt
index e840949..eb26631 100644
--- a/app/src/main/java/com/github/drunlin/webappbox/model/DatabaseManager.kt
+++ b/app/src/main/java/com/github/drunlin/webappbox/model/DatabaseManager.kt
@@ -20,7 +20,7 @@ class DatabaseManager(private val context: Context) :
 
     companion object {
         val DB_NAME = "app.db"
-        val DB_VERSION = 1
+        val DB_VERSION = 2
 
         val TABLE_APP = "app"
         val TABLE_RULE = "rule"
@@ -44,6 +44,7 @@ class DatabaseManager(private val context: Context) :
         val FULL_SCREEN = "full_screen"
         val LAUNCH_MODE = "launch_mode"
         val LOCATION = "location"
+        val TEXT_ZOOM = "text_zoom"
     }
 
     @Inject lateinit var userAgentManager: Lazy<UserAgentManager>
@@ -76,6 +77,7 @@ class DatabaseManager(private val context: Context) :
             $PATTERN text not null,
             $REGEX integer not null,
             $COLOR integer not null,
+            $TEXT_ZOOM integer not null,
             $LAUNCH_MODE text not null,
             $ORIENTATION text not null,
             $FULL_SCREEN integer not null,
@@ -89,7 +91,9 @@ class DatabaseManager(private val context: Context) :
         sql.split(";\n").filter(String::isNotBlank).map { "$it;" }.forEach { db.execSQL(it) }
     }
 
-    override fun onUpgrade(p0: SQLiteDatabase?, p1: Int, p2: Int) = Unit
+    override fun onUpgrade(db: SQLiteDatabase, oldVersion: Int, newVersion: Int) {
+        db.execSQL("ALTER TABLE $TABLE_RULE ADD COLUMN $TEXT_ZOOM integer default 100;")
+    }
 
     private fun query(table: String, columns: Array<String>, selection: String?,
               selectionArgs: Array<String>?): Cursor {
@@ -204,6 +208,7 @@ class DatabaseManager(private val context: Context) :
         values.put(PATTERN, pattern.pattern)
         values.put(REGEX, pattern.regex)
         values.put(COLOR, color)
+        values.put(TEXT_ZOOM, textZoom)
         values.put(LAUNCH_MODE, launchMode.name)
         values.put(ORIENTATION, orientation.name)
         values.put(FULL_SCREEN, fullScreen)
@@ -228,15 +233,15 @@ class DatabaseManager(private val context: Context) :
 
     fun getRules(id: Long): MutableList<Rule> {
         val list = LinkedList<Rule>()
-        val columns = arrayOf(ID, PATTERN, REGEX, COLOR, LAUNCH_MODE, ORIENTATION, FULL_SCREEN,
+        val columns = arrayOf(ID, PATTERN, REGEX, COLOR, TEXT_ZOOM, LAUNCH_MODE, ORIENTATION, FULL_SCREEN,
                 USER_AGENT, JS_ENABLE)
         val cursor = query(TABLE_RULE, columns, "$APP_ID=$id", ORDER)
         if (cursor.moveToFirst())
             do
                 list.add(Rule(cursor.getLong(0), URLPattern(cursor.getString(1), cursor.getBoolean(2)),
-                        cursor.getInt(3), LaunchMode.valueOf(cursor.getString(4)),
-                        Orientation.valueOf(cursor.getString(5)), cursor.getBoolean(6),
-                        userAgentManager.get().getUserAgent(cursor.getLong(7)), cursor.getBoolean(8)))
+                        cursor.getInt(3), cursor.getInt(4), LaunchMode.valueOf(cursor.getString(5)),
+                        Orientation.valueOf(cursor.getString(6)), cursor.getBoolean(7),
+                        userAgentManager.get().getUserAgent(cursor.getLong(8)), cursor.getBoolean(9)))
             while (cursor.moveToNext())
         cursor.close()
         return list
diff --git a/app/src/main/java/com/github/drunlin/webappbox/model/PreferenceModel.kt b/app/src/main/java/com/github/drunlin/webappbox/model/PreferenceModel.kt
index 32bfcea..8faf190 100644
--- a/app/src/main/java/com/github/drunlin/webappbox/model/PreferenceModel.kt
+++ b/app/src/main/java/com/github/drunlin/webappbox/model/PreferenceModel.kt
@@ -33,6 +33,7 @@ class PreferenceModel : Injectable, SharedPreferences.OnSharedPreferenceChangeLi
                 val orientation = Orientation.valueOf(
                         preferences.getString(PREF_ORIENTATION, Orientation.NORMAL.name))
                 _defaultRule = Rule(-1, URLPattern(), preferences.getInt(PREF_COLOR, Color.BLACK),
+                        preferences.getInt(PREF_TEXT_ZOOM, 100),
                         launchMode, orientation, preferences.getBoolean(PREF_FULL_SCREEN, false),
                         userAgent, preferences.getBoolean(PREF_ENABLE_JS, true))
             }
diff --git a/app/src/main/java/com/github/drunlin/webappbox/model/RuleManager.kt b/app/src/main/java/com/github/drunlin/webappbox/model/RuleManager.kt
index 142b11b..79a4315 100644
--- a/app/src/main/java/com/github/drunlin/webappbox/model/RuleManager.kt
+++ b/app/src/main/java/com/github/drunlin/webappbox/model/RuleManager.kt
@@ -27,12 +27,13 @@ open class RuleManager : DataManager<Rule>() {
         onMove.invoke { it(from, to) }
     }
 
-    fun update(id: Long, pattern: String, regex: Boolean, color: Int, launchMode: LaunchMode,
+    fun update(id: Long, pattern: String, regex: Boolean, color: Int, textZoom: Int, launchMode: LaunchMode,
                orientation: Orientation, fullScreen: Boolean, userAgent: UserAgent?, enableJS: Boolean) {
         val (index, rule) = rules.findIndexedValue { it.id == id }
         rule.pattern.pattern = pattern
         rule.pattern.regex = regex
         rule.color = color
+        rule.textZoom = textZoom
         rule.launchMode = launchMode
         rule.orientation = orientation
         rule.fullScreen = fullScreen
@@ -41,10 +42,10 @@ open class RuleManager : DataManager<Rule>() {
         update(index, rule)
     }
 
-    fun insert(pattern: String, regex: Boolean, color: Int, launchMode: LaunchMode,
+    fun insert(pattern: String, regex: Boolean, color: Int, textZoom: Int, launchMode: LaunchMode,
                orientation: Orientation, fullScreen: Boolean,
                userAgent: UserAgent?, enableJS: Boolean) {
-        val rule = Rule(generateId(), URLPattern(pattern, regex), color, launchMode, orientation,
+        val rule = Rule(generateId(), URLPattern(pattern, regex), color, textZoom, launchMode, orientation,
                 fullScreen, userAgent ?: userAgentManager.defaultUserAgent, enableJS)
         insert(rule)
     }
diff --git a/app/src/main/res/layout/fragment_rule_editor.xml b/app/src/main/res/layout/fragment_rule_editor.xml
index dfc4b2b..2dae2cf 100644
--- a/app/src/main/res/layout/fragment_rule_editor.xml
+++ b/app/src/main/res/layout/fragment_rule_editor.xml
@@ -36,6 +36,35 @@
                 android:layout_gravity="right|center_vertical"
                 app:color="@{rule != null ? rule.color : @android:color/black}"/>
         </FrameLayout>
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="vertical"
+            style="@style/ListPreferredItem">
+            <TextView
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:text="@string/text_zoom"
+                style="@style/ListItemTitle"/>
+            <LinearLayout
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:gravity="center_vertical">
+                <TextView
+                    android:id="@+id/textZoomText"
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:text="@{@string/text_zoom_summary(rule != null ? rule.textZoom : 100)}"
+                    tools:text="100%"
+                    style="@style/ListItemSummary"/>
+                <SeekBar
+                    android:id="@+id/textZoomSeekBar"
+                    android:layout_width="match_parent"
+                    android:layout_height="wrap_content"
+                    android:max="200"
+                    android:progress="@{rule != null ? rule.textZoom : 100}"/>
+            </LinearLayout>
+        </LinearLayout>
         <com.github.drunlin.webappbox.widget.AppSpinner
             android:id="@+id/launchModeSpinner"
             android:layout_width="match_parent"
diff --git a/app/src/main/res/raw/setup.sql b/app/src/main/res/raw/setup.sql
index 0ed26f2..3473f9d 100644
--- a/app/src/main/res/raw/setup.sql
+++ b/app/src/main/res/raw/setup.sql
@@ -5,6 +5,6 @@ INSERT INTO "user_agent" VALUES(1,'Android Phone','Mozilla/5.0 (Linux; Android 7
 INSERT INTO "user_agent" VALUES(2,'Android Tablet','Mozilla/5.0 (Linux; Android 7.0; Nexus 9 Build/NPD90G; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/51.0.2704.90 Safari/537.36 Sleipnir/3.5.4');
 INSERT INTO "user_agent" VALUES(3,'iPhone','Mozilla/5.0 (iPhone; CPU iPhone OS 10_0 like Mac OS X) AppleWebKit/602.1.50 (KHTML, like Gecko) Version/10.0 Mobile/14A5341a Safari/602.1');
 INSERT INTO "user_agent" VALUES(4,'iPad','Mozilla/5.0 (iPad; CPU OS 10_0 like Mac OS X) AppleWebKit/601.1 (KHTML, like Gecko) CriOS/53.0.2785.86 Mobile/14A5335b Safari/601.1.46');
-INSERT INTO "rule" VALUES(1,1,'.+',1,-16777216,'SINGLE_TOP','LANDSCAPE',1,0,1,1);
-INSERT INTO "rule" VALUES(2,2,'https://(www\.)?regex101\.com/.*',1,-12627531,'CLEAR_TOP','NORMAL',0,0,1,2);
-INSERT INTO "rule" VALUES(3,2,'.+',1,-16777216,'STANDARD','NORMAL',0,0,1,2);
+INSERT INTO "rule" VALUES(1,1,'.+',1,-16777216,100,'SINGLE_TOP','LANDSCAPE',1,0,1,1);
+INSERT INTO "rule" VALUES(2,2,'https://(www\.)?regex101\.com/.*',1,-12627531,100,'CLEAR_TOP','NORMAL',0,0,1,2);
+INSERT INTO "rule" VALUES(3,2,'.+',1,-16777216,100,'STANDARD','NORMAL',0,0,1,2);
diff --git a/app/src/main/res/values-zh-rCN/strings.xml b/app/src/main/res/values-zh-rCN/strings.xml
index e60fbba..5233d3a 100644
--- a/app/src/main/res/values-zh-rCN/strings.xml
+++ b/app/src/main/res/values-zh-rCN/strings.xml
@@ -102,4 +102,5 @@
         <item>全局唯一</item>
     </string-array>
     <string name="app_name">网络应用盒子</string>
+    <string name="text_zoom">文字大小</string>
 </resources>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 971a172..f0cf247 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -78,7 +78,7 @@
     <string name="ok">OK</string>
     <string name="add">Add</string>
     <string name="version">Version</string>
-    <string name="version_code" translatable="false">1.2</string>
+    <string name="version_code" translatable="false">1.3</string>
     <string name="github" translatable="false">Github</string>
     <string name="project_homepage" translatable="false">https://github.com/drunlin/webappbox</string>
     <string name="developer">Developer</string>
@@ -106,4 +106,6 @@
     <string name="pattern_summary">Links that are not matched are opened in other apps</string>
     <string name="rule_summary">Set special rules for pages</string>
     <string name="preview">Preview</string>
+    <string name="text_zoom">Text zoom</string>
+    <string name="text_zoom_summary" translatable="false">%d%%</string>
 </resources>
diff --git a/app/src/main/res/xml/settings.xml b/app/src/main/res/xml/settings.xml
index b5361f5..9a65ecf 100644
--- a/app/src/main/res/xml/settings.xml
+++ b/app/src/main/res/xml/settings.xml
@@ -1,14 +1,21 @@
 <?xml version="1.0" encoding="utf-8"?>
 <!--suppress AndroidElementNotAllowed -->
-<PreferenceScreen
-    xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:tools="http://schemas.android.com/tools">
+<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
     <PreferenceCategory
         android:title="@string/default_rule">
         <com.thebluealliance.spectrum.SpectrumPreferenceCompat
             android:key="status_bar_color"
             android:title="@string/status_bar_color"
             android:defaultValue="@android:color/black"/>
+        <android.support.v7.preference.SeekBarPreference
+            android:key="text_zoom"
+            android:title="@string/text_zoom"
+            tools:summary="100%"
+            app:showSeekBarValue="false"
+            android:max="200"
+            android:defaultValue="100"/>
         <ListPreference
             android:key="launch_mode"
             android:title="@string/launch_mode"