diff --git a/TODO b/TODO
index 05ca044..243d2d2 100644
--- a/TODO
+++ b/TODO
@@ -7,12 +7,9 @@ Note: not ordered. do whatever I/you want
 + Even Better CLI, e.g. invoke imagemagick if input is not PBM
 + Even better CUPS/IPP support
 + Even better frontend usability, more functions
-+ A better layout for mobile?
 + Make a build guide for android:
   Summary the hacks to p4a, bleak p4a recipe, p4a webview bootstrap, and AdvancedWebView
 + Try to implement enough without more dependencies
-+ Better Canvas mode, (re-)consider fabric.js
-+ Implement Document mode, (re-)consider html2canvas.js
 + ...
 
 ? Consider more control to something like 'energy'
diff --git a/build-android/0-build-android.sh b/build-android/0-build-android.sh
index e942098..994bc39 100755
--- a/build-android/0-build-android.sh
+++ b/build-android/0-build-android.sh
@@ -1,6 +1,6 @@
 #!/bin/sh
 p4a apk --private .. --dist_name="cat-printer" --package="io.github.naitlee.catprinter" --name="Cat Printer" \
-    --icon=icon.png --version="0.2.0" --bootstrap=webview --window --requirements=android,pyjnius,bleak \
+    --icon=icon.png --version="0.3.0" --bootstrap=webview --window --requirements=android,pyjnius,bleak \
     --blacklist-requirements=sqlite3,openssl --port=8095 --arch=arm64-v8a --blacklist="blacklist.txt" \
     --presplash=blank.png --presplash-color=black --add-source="advancedwebview" --orientation=user \
     --permission=BLUETOOTH --permission=BLUETOOTH_SCAN --permission=BLUETOOTH_CONNECT \
diff --git a/build-android/blacklist.txt b/build-android/blacklist.txt
index dbb68f9..b0ab2c3 100644
--- a/build-android/blacklist.txt
+++ b/build-android/blacklist.txt
@@ -6,6 +6,10 @@
 .pylintrc
 ?-*.sh
 
+# symlinks
+*.pf2
+*.pbm
+
 # junk
 __pycache__
 .directory
diff --git a/build-common/0-bundle-all.sh b/build-common/0-bundle-all.sh
index aeba9f6..65f77d5 100755
--- a/build-common/0-bundle-all.sh
+++ b/build-common/0-bundle-all.sh
@@ -1,5 +1,6 @@
 #!/bin/sh
 for i in $(find | grep -E '.*\.pyc'); do rm $i; done
+for i in $(find | grep -E '__pycache__'); do rm -d $i; done
 python3 bundle.py $1
 python3 bundle.py -w $1
 python3 bundle.py -b $1
diff --git a/printer.py b/printer.py
index 01e2d86..28a4a51 100644
--- a/printer.py
+++ b/printer.py
@@ -304,17 +304,19 @@ class PrinterDriver(Commander):
     def connect(self, name=None, address=None):
         ''' Connect to this device, and operate on it
         '''
+        self._pending_data = io.BytesIO()
         if self.fake:
             return
         if (self.device is not None and address is not None and
             (self.device.address.lower() == address.lower())):
             return
-        if self.device is not None and self.device.is_connected:
-            self.loop(
-                self.device.stop_notify(self.rx_characteristic),
-                self.device.disconnect()
-            )
-        else:
+        try:
+            if self.device is not None and self.device.is_connected:
+                self.loop(self.device.stop_notify(self.rx_characteristic))
+                self.loop(self.device.disconnect())
+        except:     # pylint: disable=bare-except
+            pass
+        finally:
             self.device = None
         if name is None and address is None:
             return
@@ -356,6 +358,7 @@ class PrinterDriver(Commander):
         devices = self.loop(
             scanner.discover(self.scan_timeout)
         )
+        devices = [dev for dev in devices if dev.name in Models]
         if identifier is not None:
             if identifier in Models:
                 devices = [dev for dev in devices if dev.name == identifier]
@@ -371,11 +374,11 @@ class PrinterDriver(Commander):
             Currently, available modes are `pbm` and `text`.
             If no devices were connected, scan & connect to one first.
         '''
+        self._pending_data = io.BytesIO()
         if self.device is None:
             self.scan(identifier, use_result=True)
         if self.device is None and not self.fake:
             error('no-available-devices-found', exception=PrinterError)
-        self._pending_data = io.BytesIO()
         if mode == 'pbm' or mode == 'default':
             printer_data = PrinterData(self.model.paper_width, file)
             self._print_bitmap(printer_data)
@@ -509,6 +512,8 @@ class PrinterDriver(Commander):
 
 # CLI procedure
 
+Printer = None
+
 def _main():
     'Main routine for direct command line execution'
     parser = argparse.ArgumentParser(
@@ -542,6 +547,8 @@ def _main():
                         help=I18n['virtual-run-on-specified-model'])
     parser.add_argument('-m', '--dump', required=False, action='store_true',
                         help=I18n['dump-the-traffic'])
+    parser.add_argument('-n', '--nothing', required=False, action='store_true',
+                        help=I18n['do-nothing'])
     args = parser.parse_args()
     info(I18n['cat-printer'])
     printer = PrinterDriver()
@@ -556,17 +563,22 @@ def _main():
     if args.fake:
         printer.fake = args.fake
         printer.model = Models[args.fake]
+    else:
+        info(I18n['connecting'])
+        printer.scan(args.identifier, use_result=True)
     printer.dump = args.dump
     if args.file == '-':
         file = sys.stdin.buffer
     else:
         file = open(args.file, 'rb')
+    if args.nothing:
+        global Printer
+        Printer = printer
+        return
     try:
-        info(I18n['connecting'])
         printer.print(
             file,
-            mode = 'text' if args.text else 'pbm',
-            identifier = args.identifier
+            mode = 'text' if args.text else 'pbm'
         )
         info(I18n['finished'])
     except KeyboardInterrupt:
diff --git a/server.py b/server.py
index 28788ca..fb450c2 100644
--- a/server.py
+++ b/server.py
@@ -39,6 +39,7 @@ mime_type = {
     'txt': 'text/plain;charset=utf-8',
     'json': 'application/json;charset=utf-8',
     'png': 'image/png',
+    'svg': 'image/svg+xml;charset=utf-8',
     'octet-stream': 'application/octet-stream'
 }
 def mime(url: str):
@@ -55,6 +56,7 @@ class PrinterServerHandler(BaseHTTPRequestHandler):
     settings = DictAsObject({
         'config_path': 'config.json',
         'version': 1,
+        'first_run': True,
         'is_android': False,
         'scan_timeout': 5.0,
         'dry_run': False
@@ -73,6 +75,14 @@ class PrinterServerHandler(BaseHTTPRequestHandler):
     def log_error(self, *_args):
         pass
 
+    def handle_one_request(self):
+        try:
+            # this handler would have only one instance
+            # broken pipe could make it die. ignore
+            super().handle_one_request()
+        except BrokenPipeError:
+            pass
+
     def do_GET(self):
         'Called when server get a GET http request'
         path = 'www' + self.path
@@ -154,6 +164,7 @@ class PrinterServerHandler(BaseHTTPRequestHandler):
         self.printer.dump = self.settings.dump
         self.printer.flip_h = self.settings.flip_h
         self.printer.flip_v = self.settings.flip_v
+        self.printer.rtl = self.settings.force_rtl
         if self.settings.printer is not None:
             name, address = self.settings.printer.split(',')
             self.printer.connect(name, address)
diff --git a/www/_load.html b/www/_load.html
index e39148b..4a0b9b1 100644
--- a/www/_load.html
+++ b/www/_load.html
@@ -4,15 +4,35 @@
 <head>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
-    <title>Python Webview Loading</title>
+    <title>Loading</title>
     <style>
         :root {
             --fore-color: #111;
             --back-color: #eee;
+            --notice-error: rgba(255, 0, 0, 0.2);
+            --font-size: 1.2rem;
+            --line-height: 1.8em;
+            --anim-time: 0.5s;
         }
         body {
             background-color: var(--back-color);
             color: var(--fore-color);
+            font-size: var(--font-size);
+            line-height: var(--line-height);
+        }
+        a:link, a:visited {
+            color: #33f;
+        }
+        a:hover, a:active {
+            color: #22f;
+        }
+        @media (prefers-reduced-motion) {
+            body {
+                transition-duration: 0ms !important;
+                transition: none;
+                animation-timing-function: steps(1);
+                animation-duration: 0ms !important;
+            }
         }
         @media (prefers-color-scheme: dark) {
             :root {
@@ -20,9 +40,78 @@
                 --back-color: #333;
             }
         }
+        @keyframes jump {
+            0% { transform: translateY(0); }
+            50% { transform: translateY(var(--font-size)); }
+            100% { transform: translateY(0); }
+        }
+        #loading-screen {
+            position: fixed;
+            top: 0;
+            left: 0;
+            width: 100%;
+            height: 100%;
+            background-color: var(--back-color);
+            display: flex;
+            flex-direction: column;
+            justify-content: center;
+            text-align: center;
+            z-index: 1;
+            opacity: 1;
+            transition: opacity var(--anim-time) var(--curve);
+        }
+        .logo {
+            background-image: url('icon.svg');
+            background-position: center;
+            background-repeat: no-repeat;
+            background-size: contain;
+            width: 80%;
+            max-width: 16em;
+            height: 80%;
+            max-height: 16em;
+            margin: 0 auto;
+        }
+        #loading-screen.hidden {
+            opacity: 0;
+        }
+        #loading-screen>.dots {
+            display: flex;
+            flex-direction: row;
+            justify-content: center;
+        }
+        #loading-screen>.dots>span {
+            display: inline-block;
+            width: var(--font-size);
+            height: var(--font-size);
+            margin: var(--font-size);
+            background-color: var(--fore-color);
+            border-radius: calc(var(--font-size) / 2);
+            animation: jump 1s ease 0s infinite;
+        }
+        #loading-screen>.dots>span:nth-child(1) { animation-delay: 0s; }
+        #loading-screen>.dots>span:nth-child(2) { animation-delay: 0.3s; }
+        #loading-screen>.dots>span:nth-child(3) { animation-delay: 0.6s; }
+
+        a {
+            transition: all var(--anim-time) ease-out;
+        }
     </style>
 </head>
 <body>
-
+    <div id="loading-screen">
+        <div class="logo"></div>
+        <div class="dots">
+            <span></span>
+            <span></span>
+            <span></span>
+        </div>
+        <noscript>
+            <p class="noscript">
+                <span>Please enable JavaScript!</span><br />
+                <a href="jslicense.html" data-i18n="javascript-license-information"
+                data-jslicense="1" >JavaScript License Information</a>
+            </p>
+        </noscript>
+    </div>
 </body>
 </html>
\ No newline at end of file
diff --git a/www/about.html b/www/about.html
new file mode 100644
index 0000000..f344f6a
--- /dev/null
+++ b/www/about.html
@@ -0,0 +1,40 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>About</title>
+    <link rel="stylesheet" href="main.css" />
+    <link rel="icon" href="icon.svg" />
+</head>
+<body>
+    <main>
+        <div>
+            <h1 data-i18n="cat-printer">Cat Printer</h1>
+            <p>
+                <span data-i18n="home-page-">Home Page:</span>
+                <a target="_blank" href="https://github.com/NaitLee/Cat-Printer">GitHub</a>
+            </p>
+            <h2 data-i18n="contributors">Contributors</h2>
+            <dl>
+                <dt>
+                    <a target="_blank" href="https://github.com/NaitLee">NaitLee</a>
+                </dt>
+                <dd data-i18n="developer">Developer</dd>
+                <dt>
+                    <a target="_blank" href="https://github.com/frankenstein91">frankenstein91</a>
+                </dt>
+                <dd data-i18n="developer">Developer</dd>
+                <dd data-i18n="translator">Translator</dd>
+                <dt data-i18n="all-testers-and-users">All testers & users</dt>
+                <dd data-i18n="everyone-is-awesome">Everyone is awesome!</dd>
+            </dl>
+            <h2 data-i18n="license">License</h2>
+            <p>This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.</p>
+            <p>This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.</p>
+            <p>You should have received a copy of the GNU General Public License along with this program. If not, see &lt;<a target="_blank" href="https://www.gnu.org/licenses/">https://www.gnu.org/licenses/</a>&gt;.</p>
+        </div>
+    </main>
+</body>
+</html>
\ No newline at end of file
diff --git a/www/i18n.js b/www/i18n.js
index 61b0264..c981429 100644
--- a/www/i18n.js
+++ b/www/i18n.js
@@ -21,24 +21,27 @@ class I18n {
      * @param {Languages} language
      */
     useLanguage(language) {
-        this.language = language;
+        if (this.language)
+            this.database[language] = this.database[this.language];
         if (!this.database[language])
             this.database[language] = {};
+        this.language = language;
     }
     /**
-     * Add data as corresponding language, also to
-     * other (added) languages as fallback
+     * Add data as corresponding language,
+     * also to other (added) languages as fallback,
+     * or override
      * @param {Languages} language
      * @param {LanguageData} data
      */
-    add(language, data) {
+    add(language, data, override = false) {
         if (!this.database[language])
             this.database[language] = {};
         for (let key in data) {
             let value = data[key];
             this.database[language][key] = value;
             for (let lang in this.database)
-                if (!this.database[lang][key])
+                if (override || !this.database[lang][key])
                     this.database[lang][key] = value;
         }
     }
diff --git a/www/icon.png b/www/icon.png
deleted file mode 100644
index d46ffb1..0000000
Binary files a/www/icon.png and /dev/null differ
diff --git a/build-android/icon.svg b/www/icon.svg
similarity index 100%
rename from build-android/icon.svg
rename to www/icon.svg
diff --git a/www/image.js b/www/image.js
index f7423a7..fa10d4e 100644
--- a/www/image.js
+++ b/www/image.js
@@ -69,8 +69,8 @@ function monoSteinberg(data, w, h, t) {
         for (let i = 0; i < w; i++) {
             p = j * w + i;
             m = data[p];
-            n = m > t ? 255 : 0;
-            o = m - n;
+            n = m > 128 ? 255 : 0;
+            o = m - n + t;
             data[p] = n;
             adjust(i + 1, j    , o * 7 / 16);
             adjust(i - 1, j + 1, o * 3 / 16);
@@ -85,100 +85,6 @@ function monoSteinberg(data, w, h, t) {
  */
 function monoHalftone(data, w, h, t) {}
 
-/**
- * My own toy algorithm used in old versions. Not so natual.  
- * It have 2 pass, horizonally and vertically.
- * @param {Uint8ClampedArray} data the grayscale data, mentioned in `monoGrayscale`. **will be modified in-place**
- * @param {number} w width of image
- * @param {number} h height of image
- * @param {number} t threshold
- */
-function monoLegacy(data, w, h, t) {
-    let data_h = data.slice();
-    let data_v = data.slice();
-    monoLegacyH(data_h, w, h, t);
-    monoLegacyV(data_v, w, h, t);
-    for (let i = 0; i < data.length; i++) {
-        data[i] = data_h[i] & data_v[i];
-    }
-}
-function monoLegacyH(data, w, h, t) {
-    let v = 0, p;
-    for (let j = 0; j < h; j++) {
-        for (let i = 0; i < w; i++) {
-            p = j * w + i;
-            v += data[p];
-            if (v >= t) {
-                data[p] = 255;
-                v = 0;
-            } else data[p] = 0;
-        }
-        v = 0;
-    }
-}
-function monoLegacyV(data, w, h, t) {
-    let v = 0, p;
-    for (let i = 0; i < w; i++) {
-        for (let j = 0; j < h; j++) {
-            p = j * w + i;
-            v += data[p];
-            if (v >= t) {
-                data[p] = 255;
-                v = 0;
-            } else data[p] = 0;
-        }
-        v = 0;
-    }
-}
-
-/**
- * Slightly modified from `monoLegacy`, but still messy.  
- * But, try the horizonal and vertical sub algorithm!
- * @param {Uint8ClampedArray} data the grayscale data, mentioned in `monoGrayscale`. **will be modified in-place**
- * @param {number} w width of image
- * @param {number} h height of image
- * @param {number} t threshold
- */
-function monoNew(data, w, h, t) {
-    let data_h = data.slice();
-    let data_v = data.slice();
-    monoNewH(data_h, w, h, t);
-    monoNewV(data_v, w, h, t);
-    for (let i = 0; i < data.length; i++) {
-        data[i] = data_h[i] & data_v[i];
-    }
-}
-function monoNewH(data, w, h, t) {
-    t = (t - 127) / 4 + 1;
-    let v = 0, p;
-    for (let j = 0; j < w; j++) {
-        for (let i = 0; i < h; i++) {
-            p = j * h + i;
-            v += data[p] + t;
-            if (v >= 255) {
-                data[p] = 255;
-                v -= 255;
-            } else data[p] = 0;
-        }
-        v = 0;
-    }
-}
-function monoNewV(data, w, h, t) {
-    t = (t - 127) / 4 + 1;
-    let v = -1, p;
-    for (let i = 0; i < h; i++) {
-        for (let j = 0; j < w; j++) {
-            p = j * h + i;
-            v += data[p] + t;
-            if (v >= 255) {
-                data[p] = 255;
-                v -= 255;
-            } else data[p] = 0;
-        }
-        v = 0;
-    }
-}
-
 /**
  * Convert a monochrome image data to PBM mono image file data.  
  * Returns a Blob containing the file data.
diff --git a/www/index.html b/www/index.html
index 248ac8f..0af3da5 100644
--- a/www/index.html
+++ b/www/index.html
@@ -5,84 +5,63 @@
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <title>Cat Printer</title>
     <link rel="stylesheet" href="main.css" />
-    <link rel="icon" href="icon.png" />
+    <link rel="icon" href="icon.svg" />
 </head>
 <body>
-    <main>
-        <div class="left">
+    <main class="hard-hidden">
+        <div class="menu-side">
             <h1 id="title" data-i18n="cat-printer">Cat Printer</h1>
             <div id="notice">
-                <noscript>
-                    <span class="noscript">Please enable JavaScript!</span>
-                </noscript>
             </div>
-            <div class="panel" id="panel-print">
-                <a href="#" data-i18n="print" data-default>Print</a>
-                <label for="device-options" data-i18n="device-">Device:</label>
-                <select id="device-options">
-                    <!-- Initialized by script -->
-                </select>
-                <button id="device-refresh" data-i18n="refresh">Refresh</button>
-                <br />
-                <label data-i18n="mode-">Mode:</label>
-                <label>
-                    <input type="radio" name="mode" value="mode-canvas" checked />
-                    <span data-i18n="canvas">Canvas</span>
-                </label>
-                <!-- <label>
-                    <input type="radio" name="mode" value="mode-document" />
-                    <span data-i18n="document">Document</span>
-                </label><br /> -->
-                <button id="insert-picture" data-i18n="insert-picture">Insert Picture</button><br />
-            </div>
-            <div class="panel expanded" id="panel-help">
-                <a href="#" data-i18n="help">Help</a>
-                <div>
-                    <p data-i18n="coming-soon-">Coming Soon...</p>
-                    <p>
-                        <!-- LibreJS doesn't work with dynamically inserted script tag. Going to complain -->
-                        <a href="jslicense.html" data-jslicense="1"
-                        data-i18n="javascript-license-information">JavaScript License Information</a>
-                    </p>
-                </div>
-            </div>
-            <div class="panel" id="panel-settings">
-                <a href="#" data-i18n="settings">Settings</a>
-                <div class="sub panel">
-                    <a href="#" data-i18n="image">Image</a>
-                    <label data-i18n="monochrome-algorithm-">Monochrome Algorithm:</label><br />
+            <div class="menu">
+                <div class="panel" id="panel-print" data-default>
+                    <label for="device-options" data-i18n="device-">Device:</label>
+                    <select id="device-options">
+                    </select>
+                    <button id="device-refresh" data-i18n="refresh">Refresh</button>
+                    <hr />
+                    <label data-i18n="mode-">Mode:</label>
+                    <label>
+                        <input type="radio" name="mode" value="mode-canvas" checked />
+                        <span data-i18n="canvas">Canvas</span>
+                    </label>
+                    <!-- <label>
+                        <input type="radio" name="mode" value="mode-document" />
+                        <span data-i18n="document">Document</span>
+                    </label><br /> -->
+                    <button id="insert-picture" data-i18n="insert-picture">Insert Picture</button>
+                    <br />
+                    <label data-i18n="process-as-">Process as:</label>
                     <label>
                         <input type="radio" name="algo" value="algo-direct" />
-                        <span data-i18n="direct">Direct</span>
+                        <span data-i18n="text">Text</span>
                     </label>
                     <label>
                         <input type="radio" name="algo" value="algo-steinberg" checked />
-                        <span data-i18n="floyd-steinberg">Floyd Steinberg</span>
-                    </label><br />
-                    <!-- <label>
-                        <input type="radio" name="algo" value="algo-halftone" />
-                        <span data-i18n="halftone">Halftone</span>
-                    </label> -->
-                    <label>
-                        <input type="radio" name="algo" value="algo-new-h" />
-                        <span data-i18n="wave">Wave</span>
+                        <span data-i18n="picture">Picture</span>
                     </label>
                     <!-- <label>
-                        <input type="radio" name="algo" value="algo-new-v" />
-                        <span data-i18n="fall">Fall</span>
-                    </label> -->
-                    <label>
-                        <input type="radio" name="algo" value="algo-legacy" />
-                        <span data-i18n="legacy">Legacy</span>
-                    </label><br />
+                        <input type="radio" name="algo" value="algo-halftone" />
+                        <span data-i18n="pattern">Pattern</span>
+                    </label> --><br />
                     <label for="threshold" data-i18n="threshold-">Threshold:</label>
-                    <input type="range" min="0" max="255" value="128" id="threshold" step="8" data-default />
+                    <input type="range" min="0" max="256" value="128" step="8" id="threshold" data-default />
                     <br />
                     <input type="checkbox" name="transparent-as-white" id="transparent-as-white" checked />
                     <label for="transparent-as-white" data-i18n="transparent-as-white">Transparent as White</label>
                 </div>
-                <div class="sub panel">
-                    <a href="#" data-i18n="printer">Printer</a>
+                <div class="panel active" id="panel-help">
+                    <div>
+                        <p data-i18n="coming-soon">Coming Soon...</p>
+                        <p>
+                            <a id="link-about" href="about.html" target="frame" data-i18n="about">About</a>
+                            <!-- LibreJS doesn't work with dynamically inserted script tag. Going to complain -->
+                            <a href="jslicense.html" data-jslicense="1"
+                            data-i18n="javascript-license-information">JavaScript License Information</a>
+                        </p>
+                    </div>
+                </div>
+                <div class="panel" id="panel-settings">
                     <label for="scan-time" data-i18n="scan-time-">Scan Time:</label>
                     <input type="number" name="scan-time" id="scan-time" min="1" max="10" value="3" />
                     <span data-i18n="-seconds">seconds</span>
@@ -91,43 +70,97 @@
                     <label for="flip-h" data-i18n="flip-horizontally">Flip Horizontally</label>
                     <input type="checkbox" name="flip-v" id="flip-v" />
                     <label for="flip-v" data-i18n="flip-vertically">Flip Vertically</label>
-                    <br />
+                    <hr />
                     <input type="checkbox" name="dry-run" id="dry-run" />
                     <label for="dry-run" data-i18n="dry-run">Dry Run</label>
                     <input type="checkbox" name="dump" id="dump" />
                     <label for="dump" data-i18n="dump-traffic">Dump Traffic</label>
+                    <br />
+                    <button id="set-accessibility">
+                        <span>🌎</span>
+                        <span data-i18n="accessibility">Accessibility</span>
+                    </button>
+                    <button class="hidden" data-panel="panel-error" data-i18n="error-message">Error Message</button>
+                    <div class="center">
+                        <button id="button-exit" data-i18n="exit">Exit</button>
+                    </div>
                 </div>
-                <div class="sub panel">
-                    <a href="#" data-i18n="system">System</a>
-                    <input type="checkbox" name="no-animation" id="no-animation" />
-                    <label for="no-animation" data-i18n="disable-page-animation">Disable Page Animation</label>
-                </div>
-                <div class="center">
-                    <button id="button-exit" data-i18n="exit">Exit</button>
+                <div class="panel" id="panel-error">
+                    <p data-i18n="you-can-seek-for-help-with-detailed-info-below">You can seek for help with detailed info below.</p>
+                    <div id="error-record"></div>
                 </div>
             </div>
-            <div class="panel hidden" id="panel-error">
-                <a href="#" data-i18n="error-message">Error Message</a>
-                <p data-i18n="you-can-seek-for-help-with-detailed-info-below">You can seek for help with detailed info below.</p>
-                <div id="error-record"></div>
+            <div class="compact-menu">
+                <div class="compact-button" data-panel="panel-print" data-i18n="print">Print</div>
+                <div class="compact-button active" data-panel="panel-help" data-i18n="help">Help</div>
+                <div class="compact-button" data-panel="panel-settings" data-i18n="settings">Settings</div>
             </div>
             <div class="center">
-                <!-- <button id="button-preview" data-i18n="preview">Preview</button> -->
-                <button id="button-print" data-i18n="print">Print</button>
+                <!--  -->
             </div>
         </div>
-        <div class="right">
+        <div class="canvas-side">
             <canvas id="control-canvas" class="disabled" width="384" height="384"></canvas>
             <div id="control-document" class="disabled" contenteditable="true"></div>
             <canvas id="preview" width="384" height="384"></canvas>
-            <div class="center">
+            <div class="center buttons">
                 <!-- <button id="canvas-expand" data-i18n="expand">Expand</button>
                 <button id="canvas-crop" data-i18n="crop">Crop</button> -->
+                <!-- <button id="button-preview" data-i18n="preview">Preview</button> -->
+                <button id="button-print" data-i18n="print">Print</button>
             </div>
+            <div class="blank"></div>
         </div>
     </main>
-    <div id="hidden" class="hidden">
+    <div id="hidden" class="hard-hidden">
         <!-- Hidden area for putting elements -->
+        <input type="file" id="file" />
+        <div id="accessibility">
+            <div>
+                <h2 data-i18n="language">Language</h2>
+                <div id="select-language">
+                </div>
+            </div>
+            <div>
+                <h2 data-i18n="layout">Layout</h2>
+                <input type="checkbox" name="no-animation" id="no-animation" />
+                <label for="no-animation" data-i18n="disable-animation">Disable Animation</label>
+                <br />
+                <input type="checkbox" name="force-rtl" id="force-rtl" />
+                <label for="force-rtl" data-i18n="right-to-left-text-order">Right-to-left text order</label>
+                <br />
+                <input type="checkbox" name="large-font" id="large-font" />
+                <label for="large-font" data-i18n="large-font">Large Font</label>
+            </div>
+        </div>
+        <iframe id="frame" src="about.html" name="frame" title="frame"></iframe>
+    </div>
+    <div id="dialog" class="hidden">
+        <div class="shade"></div>
+        <div class="content">
+            <div id="dialog-content">
+                <!-- Dialog content -->
+            </div>
+            <div id="dialog-choices">
+                <input id="dialog-input" type="text" id="dialog-input" placeholder="">
+                <hr />
+            </div>
+        </div>
+    </div>
+    <div id="loading-screen">
+        <div class="logo"></div>
+        <div class="dots">
+            <span></span>
+            <span></span>
+            <span></span>
+        </div>
+        <noscript>
+            <p class="noscript">
+                <span>Please enable JavaScript!</span><br />
+                <a href="jslicense.html" data-i18n="javascript-license-information"
+                data-jslicense="1" >JavaScript License Information</a>
+            </p>
+        </noscript>
     </div>
     <script src="loader.js"></script>
 </body>
diff --git a/www/jslicense.html b/www/jslicense.html
index d789a95..aa78474 100644
--- a/www/jslicense.html
+++ b/www/jslicense.html
@@ -5,13 +5,13 @@
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <title>JavaScript License Information</title>
     <link rel="stylesheet" href="main.css" />
-    <link rel="icon" href="icon.png" />
+    <link rel="icon" href="icon.svg" />
 </head>
 <body>
     <main>
         <div>
             <h1>JavaScript License Information</h1>
-            <p>You can see all JavaScript used along with this application are Free Software.<sup><a href="#footer-1">[1]</sup></a></p>
+            <p>You can see all JavaScript programs used along with this application are Free Software.<sup><a href="#footer-1">[1]</sup></a></p>
             <p class="center">
                 <a href="/">Go Back</a>
             </p>
@@ -70,12 +70,6 @@
                             <td><a href="main.js">main.js</a></td>
                             <td>A bundle of transpiled scripts (polyfill.js, image.js, i18n.js, main.js), for compatibility to old browsers.</td>
                         </tr>
-                        <tr>
-                            <td><a href="vconsole.js">vconsole.js</a></td>
-                            <td><a href="http://opensource.org/licenses/MIT">Expat</a></td>
-                            <td><a href="https://github.com/Tencent/vConsole">vconsole.js</a></td>
-                            <td>A mini console for debugging on mobile, will only load when explicitly invoke.</td>
-                        </tr>
                     </tbody>
                 
                 </table>
@@ -90,7 +84,7 @@
                 <a href="https://www.gnu.org/philosophy/free-sw.html">Free Software</a>
             </dt>
             <dd>
-                <span>Software that respects your freedom.</span>
+                <span>Software that respects your computing freedom.</span>
             </dd>
         </dl>
     </footer>
diff --git a/www/lang/de-DE.json b/www/lang/de-DE.json
index 357924c..0b4c9f1 100644
--- a/www/lang/de-DE.json
+++ b/www/lang/de-DE.json
@@ -1,4 +1,5 @@
 {
+    "$language": "Deutsch",
     "cat-printer": "Cat Printer",
     "printer": "Drucker",
     "device-": "Gerät:",
@@ -11,13 +12,6 @@
     "javascript-license-information": "Informationen zur JavaScript-Lizenz",
     "settings": "Einstellungen",
     "image": "Bild",
-    "monochrome-algorithm-": "Schwarzweiß-Algorithmus:",
-    "direct": "Direkt",
-    "floyd-steinberg": "Floyd Steinberg",
-    "halftone": "Halbtone",
-    "wave": "Wave",
-    "fall": "Fall",
-    "legacy": "Legacy",
     "threshold-": "Schwellwert",
     "transmission-speed-": "Übertragungsgeschwindigkeit:",
     "low": "Gering",
@@ -26,7 +20,7 @@
     "transparent-as-white": "Transparent als Weiß",
     "misc": "Sonstiges",
     "system": "System",
-    "disable-page-animation": "Seitenanimation ausschalten",
+    "disable-animation": "Seitenanimation ausschalten",
     "exit": "Exit",
     "error-message": "Fehlermeldung",
     "preview": "Vorschau",
@@ -44,7 +38,7 @@
     "please-check-if-the-printer-is-down": "Bitte prüfe, ob der Drucker ausgeschaltet ist",
     "printing": "Drucken…",
     "finished": "Fertiggestellt",
-    "coming-soon-": "Demnächst verfügbar…",
+    "coming-soon": "Demnächst verfügbar…",
     "dry-run": "Testlauf",
     "dry-run-test-print-process-only": "Testlauf: nur Probedruckvorgang",
     "you-can-close-this-page-manually": "Sie können diese Seite manuell schließen",
diff --git a/www/lang/en-US.json b/www/lang/en-US.json
index ecc0828..08715b9 100644
--- a/www/lang/en-US.json
+++ b/www/lang/en-US.json
@@ -1,4 +1,5 @@
 {
+    "$language": "English (US)",
     "cat-printer": "Cat Printer",
     "printer": "Printer",
     "device-": "Device:",
@@ -11,13 +12,6 @@
     "javascript-license-information": "JavaScript License Information",
     "settings": "Settings",
     "image": "Image",
-    "monochrome-algorithm-": "Monochrome Algorithm:",
-    "direct": "Direct",
-    "floyd-steinberg": "Floyd Steinberg",
-    "halftone": "Halftone",
-    "wave": "Wave",
-    "fall": "Fall",
-    "legacy": "Legacy",
     "threshold-": "Threshold",
     "transmission-speed-": "Transmission Speed:",
     "low": "Low",
@@ -26,7 +20,7 @@
     "transparent-as-white": "Transparent as White",
     "misc": "Misc",
     "system": "System",
-    "disable-page-animation": "Disable Page Animation",
+    "disable-animation": "Disable Animation",
     "exit": "Exit",
     "error-message": "Error Message",
     "preview": "Preview",
@@ -44,7 +38,7 @@
     "please-check-if-the-printer-is-down": "Please check if the printer is down",
     "printing": "Printing…",
     "finished": "Finished",
-    "coming-soon-": "Coming Soon…",
+    "coming-soon": "Coming Soon…",
     "dry-run": "Dry Run",
     "dry-run-test-print-process-only": "Dry Run: test print process only",
     "you-can-close-this-page-manually": "You can close this page manually",
@@ -83,5 +77,26 @@
     "flip-vertically": "Flip Vertically",
     "dump-traffic": "Dump Traffic",
     "right-to-left-text-order": "Right-to-left text order",
-    "auto-wrap-line": "Auto wrap line"
+    "auto-wrap-line": "Auto wrap line",
+    "process-as-": "Process as:",
+    "text": "Text",
+    "picture": "Picture",
+    "pattern": "Pattern",
+    "large-font": "Large Font",
+    "accessibility": "Accessibility",
+    "language": "Language",
+    "layout": "Layout",
+    "ok": "OK",
+    "cancel": "Cancel",
+    "yes": "Yes",
+    "no": "No",
+    "about": "About",
+    "home-page-": "Home Page:",
+    "contributors": "Contributors",
+    "developer": "Developer",
+    "translator": "Translator",
+    "all-testers-and-users": "All testers & users",
+    "everyone-is-awesome": "Everyone is awesome!",
+    "license": "License",
+    "exiting": "Exiting…"
 }
\ No newline at end of file
diff --git a/www/lang/list.json b/www/lang/list.json
new file mode 100644
index 0000000..f289bc1
--- /dev/null
+++ b/www/lang/list.json
@@ -0,0 +1,5 @@
+{
+    "en-US": "English (US)",
+    "zh-CN": "中文（简体）",
+    "de-DE": "Deutsch"
+}
\ No newline at end of file
diff --git a/www/lang/zh-CN.json b/www/lang/zh-CN.json
index 45f983e..067d4e2 100644
--- a/www/lang/zh-CN.json
+++ b/www/lang/zh-CN.json
@@ -1,4 +1,5 @@
 {
+    "$language": "中文（简体）",
     "cat-printer": "猫咪打印机",
     "printer": "打印机",
     "device-": "设备：",
@@ -10,14 +11,6 @@
     "help": "帮助",
     "javascript-license-information": "JavaScript 许可证信息",
     "settings": "设置",
-    "monochrome-algorithm-": "单色化算法：",
-    "direct": "直接",
-    "image": "图像",
-    "floyd-steinberg": "科学",
-    "halftone": "点状",
-    "wave": "波纹",
-    "fall": "下落",
-    "legacy": "旧版",
     "threshold-": "阈值：",
     "transmission-speed-": "传输速度：",
     "low": "低",
@@ -26,7 +19,7 @@
     "transparent-as-white": "透明为白色",
     "misc": "杂项",
     "system": "系统",
-    "disable-page-animation": "禁用页面动画",
+    "disable-animation": "禁用动画",
     "exit": "退出",
     "error-message": "错误消息",
     "preview": "预览",
@@ -41,7 +34,7 @@
     "please-check-if-the-printer-is-down": "请检查打印机是否已关闭",
     "printing": "打印中……",
     "finished": "完成",
-    "coming-soon-": "即将到来……",
+    "coming-soon": "即将到来……",
     "dry-run": "干运行",
     "dry-run-test-print-process-only": "干运行：仅测试打印流程",
     "you-can-close-this-page-manually": "您可手动关闭此页面",
@@ -79,5 +72,26 @@
     "flip-vertically": "垂直翻转",
     "dump-traffic": "转储数据",
     "right-to-left-text-order": "从右到左的文字顺序",
-    "auto-wrap-line": "自动折行"
+    "auto-wrap-line": "自动折行",
+    "process-as-": "处理方式：",
+    "text": "文本",
+    "picture": "照片",
+    "pattern": "图案",
+    "large-font": "大字体",
+    "accessibility": "无障碍",
+    "language": "语言",
+    "layout": "布局",
+    "ok": "确定",
+    "cancel": "取消",
+    "yes": "是",
+    "no": "否",
+    "about": "关于",
+    "home-page-": "主页：",
+    "contributors": "贡献者",
+    "developer": "开发者",
+    "translator": "翻译",
+    "all-testers-and-users": "所有测试及正式用户",
+    "everyone-is-awesome": "每个人都是好样的！",
+    "license": "许可证",
+    "exiting": "退出中……"
 }
\ No newline at end of file
diff --git a/www/main.css b/www/main.css
index 3a7ac44..ec46b6a 100644
--- a/www/main.css
+++ b/www/main.css
@@ -1,6 +1,7 @@
 
 :root {
-    --font-size: 1.2em;
+    --font-size: 1.2rem;
+    --line-height: 1.8em;
     --span: 8px;
     --span-half: calc(var(--span) / 2);
     --span-double: calc(var(--span) * 2);
@@ -13,9 +14,10 @@
     --canvas-back: #fff;
     --curve: cubic-bezier(.08,.82,.17,1);
     --panel-height: 20em;
-    --target-color: rgba(0, 255, 0, 0.2);
-    --notice-color: rgba(0, 0, 255, 0.2);
-    --notice-warning: rgba(255, 128, 0, 0.2);
+    --target-color: rgba(0, 255, 255, 0.2);
+    --notice-wait: rgba(0, 128, 255, 0.2);
+    --notice-note: rgba(0, 255, 0, 0.2);
+    --notice-warn: rgba(255, 128, 0, 0.2);
     --notice-error: rgba(255, 0, 0, 0.2);
 }
 
@@ -27,29 +29,41 @@ body.no-animation *::after {
     animation-timing-function: steps(1);
     animation-duration: 0ms !important;
 }
+body.large-font,
+#large-font+label {
+    font-size: calc(var(--font-size) * 1.2);
+    line-height: calc(var(--line-height) * 1.2);
+}
+body.force-rtl,
+#force-rtl+label {
+    direction: rtl;
+}
 
 body {
     border: none;
     background-color: var(--back-color);
     color: var(--fore-color);
     font-size: var(--font-size);
+    line-height: var(--line-height);
     font-family: 'Noto Sans', 'Segoe UI', sans-serif;
     overflow: auto;
     margin: 1em 0;
+    user-select: none;
 }
-h1 {
-    font-size: 1.5em;
+h1, h2 {
     font-weight: normal;
     margin: var(--span-half) 0;
 }
+h1 { font-size: 1.5em; }
+h2 { font-size: 1.2em; }
 a:link, a:visited {
     color: #33f;
 }
 a:hover, a:active {
     color: #22f;
 }
-a {
-    transition: all var(--anim-time) ease-out;
+a+a {
+    margin-left: var(--font-size);
 }
 .center {
     text-align: center;
@@ -57,16 +71,23 @@ a {
 button, input, select, textarea {
     font: inherit;
     color: var(--fore-color);
+    /* background-color: var(--back-color); */
+    background-color: transparent;
+}
+select[multiple] {
+    width: 8em;
+    padding: var(--border);
+    margin: var(--span-half) var(--span);
 }
 button, input[type="number"], input[type="text"], select {
     margin: var(--span-half) var(--span);
     border: var(--border) solid var(--fore-color);
     padding: var(--span-half) var(--span);
-    background-color: transparent;
     transition: all var(--anim-time) var(--curve);
     cursor: pointer;
     min-width: 6em;
     display: inline-block;
+    line-height: calc(var(--font-size) + var(--span));
 }
 input[type="number"], input[type="text"] {
     width: 6em;
@@ -80,37 +101,50 @@ button:hover {
 button:active {
     box-shadow: 0 0 var(--span) inset var(--fore-color);
 }
+@keyframes notice-fade {
+    to { background-color: transparent; }
+}
+@keyframes notice-wait {
+    50% { background-color: transparent; }
+}
 #notice {
     min-height: var(--font-size);
-    background-color: var(--notice-color);
-    /* border: var(--border) solid var(--fore-color); */
 }
-#notice.warning, #button-exit {
-    background-color: var(--notice-warning);
+#notice span {
+    display: block;
 }
-#notice.error {
+#notice .note {
+    background-color: var(--notice-note);
+    animation: notice-fade 1s ease-out 1s 1 forwards;
+}
+#notice .wait {
+    background-color: var(--notice-wait);
+    animation: notice-wait 2s ease-in-out 0s infinite forwards;
+}
+#notice .warn {
+    background-color: var(--notice-warn);
+    animation: notice-fade 1s ease-out 1s 1 forwards;
+}
+#notice .error {
     background-color: var(--notice-error);
+    animation: notice-fade 1s ease-out 1s 1 forwards;
+}
+#button-exit {
+    background-color: var(--notice-warn);
 }
 .noscript {
+    margin: var(--span-double);
+    text-align: center;
     background-color: var(--notice-error);
+    display: block;
 }
 main, header, footer {
     max-width: 45em;
     margin: 1em auto;
     display: flex;
     flex-direction: row;
-    /* flex-wrap: wrap; */
 }
-main>.left {
-    flex-grow: 1;
-    /* position: sticky; */
-    /* top: 0; */
-    height: 100%;
-    overflow: auto;
-    margin: var(--span);
-    min-width: 12em;
-}
-main>.right {
+main>.canvas-side {
     flex-grow: 0;
     margin: 0 auto;
     height: 100%;
@@ -118,6 +152,40 @@ main>.right {
     text-align: center;
     min-width: calc(var(--paper-width) + var(--border-double) + var(--span-double));
 }
+main>.menu-side {
+    flex-grow: 1;
+    position: sticky;
+    top: 0;
+    height: 100%;
+    overflow: auto;
+    margin: var(--span);
+    min-width: 12em;
+}
+main>.menu-side>.menu {
+    border: var(--border) solid var(--fore-color);
+    border-bottom: none;
+    margin-top: var(--span);
+}
+.compact-menu {
+    display: flex;
+    flex-direction: row;
+    justify-content: space-around;
+    background-color: var(--back-color);
+}
+.compact-button {
+    width: max-content;
+    height: 2em;
+    flex-grow: 1;
+    line-height: 2em;
+    text-align: center;
+    cursor: pointer;
+    border-top: var(--border) solid var(--fore-color);
+    border-bottom: var(--border) solid transparent;
+}
+.compact-button.active {
+    border: var(--border) solid var(--fore-color);
+    border-top: var(--border) solid transparent;
+}
 canvas#preview, canvas#control-canvas, #control-document {
     border: var(--border) solid var(--fore-color);
     background-color: var(--canvas-back);
@@ -157,54 +225,17 @@ p {
     margin: var(--span) 0;
 }
 .panel {
-    border: var(--border) solid currentColor;
-    height: calc(var(--font-size) + 8px);
     overflow: hidden;
-    /* scrollbar-width: thin; */
-    transition: height var(--anim-time) var(--curve);
-    padding: 0 var(--span);
-    margin: var(--span) 0;
+    height: 0;
 }
-.panel::before {
-    float: left;
-}
-.panel:not(.sub)::before { content: '📌'; }
-.panel.sub::before { content: '📎'; }
-.panel.sub {
-    border-width: var(--border) 0 0 0;
-}
-.panel.expanded {
+.panel.active {
     height: var(--panel-height);
-    animation: delay-scrollable var(--anim-time) steps(1) 0s 1 forwards;
+    padding: var(--span-double) var(--span);
     /* overflow-y: scroll; */
 }
-.panel.sub.expanded {
+.panel.sub.active {
     height: calc(var(--panel-height) / 2);
 }
-.panel>:nth-child(1),
-.panel>:nth-child(1):link,
-.panel>:nth-child(1):visited {
-    display: block;
-    margin: var(--span-half);
-    text-decoration: none;
-    text-align: center;
-    color: var(--fore-color);
-}
-.panel>:nth-child(1)::before {
-    content: '>>';
-    display: inline-block;
-    position: relative;
-    opacity: 0;
-    width: 0;
-    overflow: visible;
-    right: 2.5em;
-    transition: all var(--anim-time) var(--curve);
-}
-.panel>:nth-child(1):hover::before,
-.panel>:nth-child(1):active::before {
-    opacity: 1;
-    right: 1.5em;
-}
 input[type="range"] {
     width: 10em;
     vertical-align: middle;
@@ -218,7 +249,16 @@ input[type="range"] {
 .hint {
     animation: hint 3s ease-out 0.1s infinite;
 }
-#hidden, .hidden { display: none; }
+.hidden {
+    /* visibility: hidden; */
+    height: 0;
+    overflow: hidden;
+    opacity: 0;
+    pointer-events: none;
+}
+#hidden, .hard-hidden {
+    display: none;
+}
 #error-record {
     font-family: 'DejaVu Sans Mono', 'Consolas', monospace;
     width: 100%;
@@ -244,11 +284,148 @@ dl {
     margin: var(--span) 0;
     display: block;
 }
+dd { display: inline; }
+dd+dd { margin-left: var(--font-size); }
 hr {
     border: none;
     border-top: var(--border) solid var(--fore-color);
 }
+#frame {
+    width: 100%;
+    height: inherit;
+    border: none;
+    background-color: transparent;
+}
+.blank {
+    height: 0em;
+}
+.shade {
+    position: fixed;
+    width: 100%;
+    height: 100%;
+    top: 0;
+    left: 0;
+    background-color: var(--back-color);
+    opacity: 0.95;
+    z-index: -1;
+}
+#dialog {
+    position: fixed;
+    width: 100%;
+    top: calc(50% - 10em);
+    text-align: center;
+    z-index: 2;
+    opacity: 2;
+    transition: opacity var(--anim-time) var(--curve);
+}
+#dialog>.content {
+    max-width: 100%;
+    box-sizing: border-box;
+    width: 40em;
+    margin: auto;
+    border: var(--border) solid var(--fore-color);
+    transition: transform var(--anim-time) var(--curve);
+}
+#dialog.hidden {
+    opacity: 0;
+    height: unset;
+}
+#dialog.hidden>.content {
+    transform: scaleY(0);
+}
+#dialog-content {
+    height: 10em;
+    margin: auto;
+    padding: var(--span);
+}
+#dialog-choices {
+    margin: auto;
+    padding: var(--span);
+}
+#choice-input {
+    max-width: 100%;
+    width: 16em;
+}
+#accessibility {
+    text-align: initial;
+    display: flex;
+    flex-direction: row;
+}
+#accessibility>*:nth-child(1) {
+    flex-grow: 1;
+}
+#select-language {
+    width: calc(100% - var(--span-double));
+    height: 8em;
+    border: var(--border) solid var(--fore-color);
+    padding: var(--span);
+    margin: var(--span);
+    box-sizing: border-box;
+}
+#select-language option {
+    cursor: pointer;
+}
+#select-language option:hover {
+    text-decoration: underline;
+}
+#accessibility>*:nth-child(2) {
+    flex-grow: 1;
+}
+@keyframes jump {
+    0% { transform: translateY(0); }
+    50% { transform: translateY(var(--font-size)); }
+    100% { transform: translateY(0); }
+}
+#loading-screen {
+    position: fixed;
+    top: 0;
+    left: 0;
+    width: 100%;
+    height: 100%;
+    background-color: var(--back-color);
+    display: flex;
+    flex-direction: column;
+    justify-content: center;
+    text-align: center;
+    z-index: 1;
+    opacity: 1;
+    transition: opacity var(--anim-time) var(--curve);
+}
+.logo {
+    background-image: url('icon.svg');
+    background-position: center;
+    background-repeat: no-repeat;
+    background-size: contain;
+    width: 80%;
+    max-width: 16em;
+    height: 80%;
+    max-height: 16em;
+    margin: 0 auto;
+}
+#loading-screen.hidden {
+    opacity: 0;
+}
+#loading-screen>.dots {
+    display: flex;
+    flex-direction: row;
+    justify-content: center;
+}
+#loading-screen>.dots>span {
+    display: inline-block;
+    width: var(--font-size);
+    height: var(--font-size);
+    margin: var(--font-size);
+    background-color: var(--fore-color);
+    border-radius: calc(var(--font-size) / 2);
+    animation: jump 1s ease 0s infinite;
+}
+#loading-screen>.dots>span:nth-child(1) { animation-delay: 0s; }
+#loading-screen>.dots>span:nth-child(2) { animation-delay: 0.3s; }
+#loading-screen>.dots>span:nth-child(3) { animation-delay: 0.6s; }
 
+a {
+    transition: all var(--anim-time) ease-out;
+}
 @keyframes delay-scrollable {
     from { overflow: hidden; }
     to { overflow: auto; }
@@ -256,23 +433,69 @@ hr {
 @media (max-width: 800px) {
     :root {
         --panel-height: 16em;
-        /* --font-size: 1em; */
+        --font-size: 1em;
     }
     main {
         flex-direction: column;
     }
-    main>.left {
-        /* height: 16em; */
-        overflow: auto;
-        width: calc(100% - var(--span-double) - var(--border-double));
-    }
-    main>.right {
+    #title { display: none; }
+    main>.canvas-side {
         min-width: unset;
+        width: 100%;
+        overflow-x: hidden;
+        overflow-y: auto;
+        position: fixed;
+        top: var(--line-height);
+        height: calc(100% - var(--panel-height) - 2em);
+        z-index: 0;
+    }
+    main>.canvas-side>.buttons,
+    main>.menu-side>.buttons {
+        position: sticky;
+        bottom: 2em;
+        width: 100%;
+        z-index: 1;
+    }
+    main>.canvas-side>.buttons button,
+    main>.menu-side>.buttons button {
+        background-color: var(--back-color);
+    }
+    main>.menu-side {
+        overflow-x: hidden;
+        overflow-y: auto;
+        position: fixed;
+        background-color: var(--back-color);
+        top: unset;
+        bottom: 0;
+        left: 0;
+        height: var(--panel-height);
+        margin: 0;
+        width: 100%;
+        box-sizing: border-box;
+    }
+    main>.menu-side>.menu {
+        height: var(--panel-height);
+        margin: 0;
+    }
+    #notice {
+        position: fixed;
+        top: 0;
+        width: 100%;
+    }
+    main>.menu-side>.compact-menu {
+        position: fixed;
+        bottom: 0;
+        width: 100%;
+        z-index: 0;
+    }
+    .blank {
+        height: 2em;
     }
 }
 @media (max-width: 384px) {
     canvas#preview, canvas#control-canvas, #control-document {
-        width: calc(100% - var(--border-double));
+        width: 100%;
+        box-sizing: border-box;
     }
 }
 @media (prefers-color-scheme: dark) {
@@ -288,7 +511,18 @@ hr {
         color: #77f;
     }
     canvas#preview, canvas#control-canvas, #control-document {
-        filter: brightness(0.5);
+        filter: brightness(0.6);
+    }
+    .logo {
+        filter: brightness(0.6);
+    }
+}
+@media (prefers-reduced-motion) {
+    body {
+        transition-duration: 0ms !important;
+        transition: none;
+        animation-timing-function: steps(1);
+        animation-duration: 0ms !important;
     }
 }
 @font-face {
diff --git a/www/main.js b/www/main.js
index 5e03596..4b4056b 100644
--- a/www/main.js
+++ b/www/main.js
@@ -7,7 +7,7 @@
  * Double-tap the "Cat Printer" title to activate
  */
 function debug() {
-    let script = document.createElement('script');
+    const script = document.createElement('script');
     script.src = 'vconsole.js';
     document.body.appendChild(script);
     script.addEventListener('load', () => new window.VConsole());
@@ -17,15 +17,16 @@ document.getElementById('title').addEventListener('dblclick', debug);
 var hidden_area = document.getElementById('hidden');
 
 const hint = (function() {
-    let hints = [];
-    let callback = (event) => {
+    let hints;
+    const callback = (event) => {
         event.stopPropagation();
         event.currentTarget.classList.remove('hint');
         event.currentTarget.removeEventListener('click', callback);
     }
     return function(selector) {
-        hints.forEach(element => element.classList.remove('hint'));
-        hints = document.querySelectorAll(selector);
+        if (hints)
+            hints.forEach(element => element.classList.remove('hint'));
+        hints = typeof selector === 'string' ? document.querySelectorAll(selector) : selector;
         hints.forEach(element => {
             element.classList.add('hint');
             element.addEventListener('click', callback);
@@ -33,28 +34,95 @@ const hint = (function() {
     }
 })();
 
-class _Notice {
-    element;
-    constructor() {
-        this.element = document.getElementById('notice');
+const Notice = (function() {
+    const notice = document.getElementById('notice');
+    let last_span;
+    function put(message, things, class_name) {
+        let text = i18n(message, things) || message;
+        if (last_span) last_span.remove();
+        let span = document.createElement('span');
+        span.innerText = text;
+        span.classList.add(class_name);
+        notice.appendChild(span);
+        last_span = span;
     }
-    _message(message, things) {
-        this.element.innerText = i18n(message, things) || message;
+    return {
+        note: (message, things) => put(message, things, 'note'),
+        wait: (message, things) => put(message, things, 'wait'),
+        warn: (message, things) => put(message, things, 'warn'),
+        error: (message, things) => put(message, things, 'error')
     }
-    makeLogger(class_name) {
-        return (message, things) => {
-            this.element.classList.value = class_name;
-            this._message(message, things);
+})();
+
+const Dialog = (function() {
+    const dialog = document.getElementById('dialog');
+    const dialog_content = document.getElementById('dialog-content');
+    const dialog_choices = document.getElementById('dialog-choices');
+    const dialog_input = document.getElementById('dialog-input');
+    let last_choices;
+    function clean_up() {
+        if (last_choices)
+            for (let choice of last_choices)
+                choice.remove();
+        // elements
+        for (let element of dialog_content.children)
+            hidden_area.appendChild(element);
+        // text nodes
+        for (let node of dialog_content.childNodes)
+            node.remove();
+    }
+    function show(argument, as_string = false) {
+        dialog.classList.remove('hidden');
+        if (as_string)
+            dialog_content.innerText = argument;
+        else
+            dialog_content.appendChild(document.querySelector(argument));
+    }
+    function apply_callback(callback, have_input = false, ... choices) {
+        last_choices = [];
+        dialog_input.value = '';
+        dialog_input.style.display = have_input ? 'unset' : 'none';
+        for (let choice of choices) {
+            let button = document.createElement('button');
+            button.setAttribute('data-i18n', choice);
+            button.innerText = i18n(choice);
+            if (!have_input)
+                button.addEventListener('click', () => dialog_input.value = choice);
+            dialog_choices.appendChild(button);
+            last_choices.push(button);
+        }
+        last_choices[0].addEventListener('click', () => {
+            if (callback) callback(dialog_input.value);
+            dialog.classList.add('hidden');
+        });
+        if (last_choices.length > 1)
+            last_choices[1].addEventListener('click', () => {
+                if (callback) callback(null);
+                dialog.classList.add('hidden');
+            });
+        hint([last_choices[0]]);
+    }
+    return {
+        alert: function(selector, callback, as_string = false) {
+            clean_up();
+            apply_callback(callback, false, 'ok');
+            show(selector, as_string);
+        },
+        confirm: function(selector, callback, as_string = false) {
+            clean_up();
+            apply_callback(callback, false, 'yes', 'no');
+            show(selector, as_string);
+        },
+        prompt: function(selector, callback, as_string = false) {
+            clean_up();
+            apply_callback(callback, true, 'ok', 'cancel');
+            show(selector, as_string);
         }
     }
-    notice = this.makeLogger('notice');
-    warn = this.makeLogger('warning');
-    error = this.makeLogger('error');
-}
-
-const Notice = new _Notice();
+})();
 
 class _ErrorHandler {
+    // TODO make better
     recordElement;
     constructor() {
         this.recordElement = document.getElementById('error-record');
@@ -65,8 +133,11 @@ class _ErrorHandler {
      */
     report(error, output) {
         Notice.error('error-happened-please-check-error-message');
-        let hidden_panel = this.recordElement.parentElement;
-        if (hidden_panel) hidden_panel.classList.remove('hidden');
+        let button = document.querySelector('button[data-panel="panel-error"]');
+        if (button) {
+            button.classList.remove('hidden');
+            button.click();
+        }
         let div = document.createElement('div');
         div.innerText = (error.stack || (error.name + ': ' + error.message)) + '\n' + output;
         this.recordElement.appendChild(div);
@@ -150,57 +221,21 @@ function putEvent(selector, type, callback, thisArg) {
     return new EventPutter(selector, type, callback, thisArg);
 }
 
-class PanelController {
-    last;
-    panels;
-    outerPanels;
-    subPanels;
-    constructor(selector = '.panel') {
-        const class_expanded = 'expanded';
-        const class_sub = 'sub';
-        let panels = this.panels = [... document.querySelectorAll(selector)];
-        let outer_panels = this.outerPanels = panels.filter(e => !e.classList.contains(class_sub));
-        let sub_panels = this.subPanels = panels.filter(e => e.classList.contains(class_sub));
-        const expand = (panel) => panel.classList.add(class_expanded);
-        const fold = (panel) => {
-            panel.classList.remove(class_expanded);
-        }
-        const fold_all_outer = () => outer_panels.forEach(e => fold(e));
-        const fold_all_sub = () => sub_panels.forEach(e => fold(e));
-        // const fold_all = () => panels.forEach(e => e.classList.remove(class_expanded));
-        fold_all_outer();
-        putEvent(selector + '>:nth-child(1)', 'click', event => {
+(function() {
+    let panels = document.querySelectorAll('.panel');
+    let buttons = document.querySelectorAll('*[data-panel]');
+    panels.forEach(panel => {
+        let button = document.querySelector(`*[data-panel="${panel.id}"]`);
+        if (button) button.addEventListener('click', event => {
             event.stopPropagation();
-            event.cancelBubble = true;
-            let current = event.currentTarget.parentElement,
-                last = this.last;
-            this.last = current;
-            if (!last) {
-                expand(current);
-                this.last = current;
-                return;
-            }
-            let is_sub = current.classList.contains(class_sub),
-                last_is_sub = last.classList.contains(class_sub);
-            if (current.classList.contains(class_expanded)) {
-                fold(current);
-                return;
-            }
-            fold_all_outer();
-            if (is_sub && last_is_sub) {
-                fold(last);
-                expand(current.parentElement);
-                last.scrollTo(0, 0);
-            } else if (is_sub && !last_is_sub) {
-                fold_all_sub();
-                expand(last);
-            } else if (!is_sub && last_is_sub) {
-                last.parentElement.scrollTo(0, 0);
-            }
-            expand(current);
-        }, this);
-    }
-}
+            panels.forEach(p => p.classList.remove('active'));
+            buttons.forEach(b => b.classList.remove('active'));
+            panel.classList.add('active');
+            button.classList.add('active');
+        });
+        if (panel.hasAttribute('data-default')) button.click();
+    });
+})();
 
 class CanvasController {
     /** @type {HTMLCanvasElement} */
@@ -211,6 +246,7 @@ class CanvasController {
     isCanvas;
     algorithm;
     threshold;
+    thresholdRange;
     transparentAsWhite;
     previewData;
     static defaultHeight = 384;
@@ -226,6 +262,7 @@ class CanvasController {
         this.canvas = document.getElementById('control-canvas');
         this.div = document.getElementById('control-document');
         this.height = CanvasController.defaultHeight;
+        this.thresholdRange = document.getElementById('threshold');
 
         putEvent('input[name="mode"]', 'change', (event) => this.enableMode(event.currentTarget.value), this);
         putEvent('input[name="algo"]', 'change', (event) => this.useAlgorithm(event.currentTarget.value), this);
@@ -259,6 +296,7 @@ class CanvasController {
     }
     useAlgorithm(name) {
         this.algorithm = name;
+        this.thresholdRange.value = 128;
         this.activatePreview();
     }
     expand(length = CanvasController.defaultHeight) {
@@ -267,7 +305,7 @@ class CanvasController {
     crop() {}
     activatePreview() {
         let preview = this.preview;
-        let t = this.threshold;
+        let t = Math.min(this.threshold, 255);
         if (this.isCanvas) {
             let canvas = this.canvas;
             let w = canvas.width, h = canvas.height;
@@ -281,7 +319,7 @@ class CanvasController {
                     monoDirect(mono_data, w, h, t);
                     break;
                 case 'algo-steinberg':
-                    monoSteinberg(mono_data, w, h, t);
+                    monoSteinberg(mono_data, w, h, Math.floor(t / 2 - 64));
                     break;
                 case 'algo-halftone':
                     // monoHalftone(mono_data, w, h, t);
@@ -291,7 +329,7 @@ class CanvasController {
                     monoNew(mono_data, w, h, t);
                     break;
                 case 'algo-new-h':
-                    monoNewH(mono_data, w, h, t);
+                    monoNewH(mono_data, w, h, Math.floor(t / 2 - 64));
                     break;
                 case 'algo-new-v':
                     monoNewV(mono_data, w, h, t);
@@ -325,7 +363,7 @@ class CanvasController {
                     context.drawImage(img, 0, 0, canvas.width, canvas.height);
                     this.crop();
                     this.activatePreview();
-                    hint('#button-print, #panel-settings');
+                    hint('#button-print');
                 });
             }
         }
@@ -344,10 +382,68 @@ class CanvasController {
     }
 }
 
+/** @param {Document} doc */
+function applyI18nToDom(doc) {
+    doc = doc || document;
+    let elements = doc.querySelectorAll('*[data-i18n]');
+    let i18n_data, translated_string;
+    elements.forEach(element => {
+        i18n_data = element.getAttribute('data-i18n');
+        translated_string = i18n(i18n_data);
+        if (translated_string === i18n_data) return;
+        // element.innerText = translated_string;
+        if (element.firstChild.textContent !== translated_string)
+            element.firstChild.textContent = translated_string;
+    });
+}
+async function initI18n() {
+    if (typeof i18n === 'undefined') return;
+    /** @type {HTMLOptionElement} */
+    let language_options = document.getElementById('select-language');
+    /** @type {{ [code: string]: string }} */
+    let list = await fetch('/lang/list.json').then(r => r.json());
+    let use_language = async (value) => {
+        i18n.useLanguage(value);
+        i18n.add(value, await fetch(`/lang/${value}.json`).then(r => r.json()), true);
+        applyI18nToDom();
+    }
+    for (let code in list) {
+        let option = document.createElement('option');
+        option.value = code;
+        option.innerText = list[code];
+        option.addEventListener('click', (event) => {
+            let option = event.currentTarget;
+            let value = option.value;
+            use_language(value);
+        });
+        language_options.appendChild(option);
+    }
+    apply_default:
+    for (let code of navigator.languages) {
+        if (list[code]) {
+            for (let option of language_options.children) {
+                if (option.value === code) {
+                    // option.setAttribute('data-default', '');
+                    option.setAttribute('data-default', '');
+                    option.click();
+                    i18n.useLanguage(navigator.languages[0]);
+                    for (let language of navigator.languages) {
+                        if (!list[language]) return;
+                        let data = await fetch(`/lang/${language}.json`)
+                            .then(response => response.ok ? response.json() : null);
+                        if (data !== null) {
+                            i18n.add(language, data);
+                        }
+                    }
+                    break apply_default;
+                }
+            }
+        }
+    }
+}
+
 class Main {
     promise;
-    /** @type {PanelController} */
-    panelController;
     /** @type {CanvasController} */
     canvasController;
     deviceOptions;
@@ -367,23 +463,38 @@ class Main {
         this.setters = {};
         // window.addEventListener('unload', () => this.exit());
         this.promise = new Promise(async (resolve, reject) => {
-            await this.initI18n();
-            this.panelController = new PanelController();
+            await initI18n();
+            /** @type {HTMLIFrameElement} */
+            let iframe = document.getElementById('frame');
+            iframe.addEventListener('load', () => {
+                applyI18nToDom(iframe.contentDocument);
+            });
             this.canvasController = new CanvasController();
             putEvent('#button-exit', 'click', this.exit, this);
             putEvent('#button-print', 'click', this.print, this);
             putEvent('#device-refresh', 'click', this.searchDevices, this);
+            putEvent('#set-accessibility', 'click', () => Dialog.alert('#accessibility'));
+            putEvent('#link-about', 'click', () => Dialog.alert('#frame'));
             this.attachSetter('#scan-time', 'change', 'scan_timeout');
             this.attachSetter('#device-options', 'input', 'printer');
             this.attachSetter('input[name="algo"]', 'change', 'mono_algorithm');
             this.attachSetter('#transparent-as-white', 'change', 'transparent_as_white');
+            this.attachSetter('#select-language option', 'click', 'language');
             this.attachSetter('#dry-run', 'change', 'dry_run',
-                (checked) => checked && Notice.notice('dry-run-test-print-process-only')
+                (checked) => checked && Notice.note('dry-run-test-print-process-only')
             );
             this.attachSetter('#no-animation', 'change', 'no_animation',
                 (checked) => checked ? document.body.classList.add('no-animation')
                     : document.body.classList.remove('no-animation')
             );
+            this.attachSetter('#large-font', 'change', 'large_font',
+                (checked) => checked ? document.body.classList.add('large-font')
+                    : document.body.classList.remove('large-font')
+            );
+            this.attachSetter('#force-rtl', 'change', 'force_rtl',
+                (checked) => checked ? document.body.classList.add('force-rtl')
+                    : document.body.classList.remove('force-rtl')
+            );
             this.attachSetter('#threshold', 'change', 'threshold',
                 (value) => this.canvasController.threshold = value
             );
@@ -392,6 +503,8 @@ class Main {
             this.attachSetter('#dump', 'change', 'dump');
             await this.loadConfig();
             this.searchDevices();
+            document.querySelector('main').classList.remove('hard-hidden');
+            document.getElementById('loading-screen').classList.add('hidden');
             resolve();
         });
     }
@@ -409,6 +522,8 @@ class Main {
      */
     async loadConfig() {
         this.settings = await callApi('/query');
+        if (this.settings['first_run'])
+            Dialog.alert('#accessibility', () => this.set({ first_run: false }));
         for (let key in this.settings) {
             let value = this.settings[key];
             if (this.setters[key] === undefined) continue;
@@ -423,8 +538,14 @@ class Main {
                         if (element.value !== value) return;
                         element.checked = value;
                         break;
-                    default:
+                    case 'text':
+                    case 'number':
+                    case 'range':
                         element.value = value;
+                        break;
+                    default:
+                        if (element.value === value)
+                            element.click();
                 }
                 element.dispatchEvent(new Event('change'));
             });
@@ -461,11 +582,12 @@ class Main {
         }).bind(this), this);
     }
     async exit() {
+        Notice.wait('exiting');
         await this.set(this.settings);
         await callApi('/exit');
         window.close();
         // Browser may block the exit
-        Notice.notice('you-can-close-this-page-manually');
+        Notice.note('you-can-close-this-page-manually');
     }
     /** @param {Response} response */
     async bluetoothProblemHandler(response) {
@@ -473,24 +595,25 @@ class Main {
         let error_details = await response.json();
         if (
             error_details.name === 'org.bluez.Error.NotReady' ||
-            error_details.details.indexOf('not turned on') !== -1 ||
-            error_details.details.indexOf('WinError -2147020577') !== -1
+            error_details.name === 'org.freedesktop.DBus.Error.UnknownObject' ||
+            error_details.details.includes('not turned on') ||
+            error_details.details.includes('WinError -2147020577')
         ) Notice.warn('please-enable-bluetooth');
         else throw new Error('Unknown Bluetooth Problem');
         return null;
     }
     async searchDevices() {
-        Notice.notice('scanning-for-devices');
+        Notice.wait('scanning-for-devices');
         let search_result = await callApi('/devices', null, this.bluetoothProblemHandler);
         if (search_result === null) return;
         let devices = search_result.devices;
         [... this.deviceOptions.children].forEach(e => e.remove());
         if (devices.length === 0) {
-            Notice.notice('no-available-devices-found');
+            Notice.note('no-available-devices-found');
             hint('#device-refresh');
             return;
         }
-        Notice.notice('found-0-available-devices', [devices.length]);
+        Notice.note('found-0-available-devices', [devices.length]);
         hint('#insert-picture');
         devices.forEach(device => {
             let option = document.createElement('option');
@@ -501,12 +624,12 @@ class Main {
         this.deviceOptions.dispatchEvent(new Event('input'));
     }
     async print() {
-        Notice.notice('printing');
+        Notice.wait('printing');
         await fetch('/print', {
             method: 'POST',
             body: this.canvasController.makePbm()
         }).then(async (response) => {
-            if (response.ok) Notice.notice('finished')
+            if (response.ok) Notice.note('finished')
             else {
                 let error_data = await response.json();
                 if (/address.+not found/.test(error_data.details))
@@ -519,28 +642,6 @@ class Main {
             }
         });
     }
-    async initI18n() {
-        if (typeof i18n === 'undefined') return;
-        i18n.useLanguage(navigator.languages[0]);
-        for (let language of navigator.languages) {
-            let data = await fetch(`/lang/${language}.json`)
-                .then(response => response.ok ? response.json() : null);
-            if (data !== null) {
-                i18n.add(language, data);
-                console.log('Loaded language:', language);
-            }
-        }
-        let elements = document.querySelectorAll('*[data-i18n]');
-        let i18n_data, translated_string;
-        elements.forEach(element => {
-            i18n_data = element.getAttribute('data-i18n');
-            translated_string = i18n(i18n_data);
-            if (translated_string === i18n_data) return;
-            // element.innerText = translated_string;
-            if (element.firstChild.textContent !== translated_string)
-                element.firstChild.textContent = translated_string;
-        });
-    }
 }
 
 var main = new Main();