Step 1: Add OneUICSS library and make your app responsive

OneUICSS is the Library by Samsung that allows developers to have a responsive web app and a good user experience that feels second nature. It's designed for better reachability with integrated Bixby features like Bixby Routines.

For more information visit:

In your starter kit, the library is already downloaded under css/oui-css.

In order to start using it, in your index.html add the following line inside <head></head>

<link rel="stylesheet" type="text/css" href="css/oui-css/oui.css">

Your app is looking much better now right? We have one more detail, One UI works by adding the related classes to each html element. Let's do it with the HEX input element, add the following classes:

<h2 class="oui-bubble-title">HEX</h2>
<input type="text" class="oui-input-textual current-color-text" onchange="convertColor(this.value)" placeholder="#FFFFFF">

Step 2: Add a web app manifest

The web app manifest is a JSON file that allows you to control how your app appears to the user and ensures that progressive web apps are discoverable. It describes the name of the app, the start URL, icons, and all of the other details necessary to transform the website into an app.

You can create manifest.webmanifest manually under your project with the following code:

{"name" : "pigment",
    "short_name" : "pigment",
    "description" : "Pigment App color conversion",
    "start_url" : "",
    "lang" : "English",
    "display" : "standalone",
    "theme_color": "#3d3d3d",
    "background_color": "#f2f2f2",
    "orientation" : "portrait",
    "icons": [ {
       "src": "/images/pigment-ico.png",
       "sizes": "192x192",
       "type": "image/png"
       "src": "/images/pigment-ico.png",
       "sizes": "512x512",
       "type": "image/png"

There are different attributes that you can provide to create your manifest file, if you want to add more information and see which attributes are available we strongly recommend using PWA builder.

  • Go to

  • In glitch, go to Share menu, Live App and copy the URL

  • Paste the URL in PWA builder website and press start

You will see the current status of your PWA. Select View Generated Manifest, copy and paste the JSON generated under a new file called manifest.webmanifest in your project. Add the following code to your start page:

<link rel='manifest' href='/manifest.webmanifest'>

Step 3: Add a service worker

A service worker allows web developers to intercept and control how a web browser handles its network requests and asset caching. With service workers, web developers can create reliably fast web pages and offline experiences. There are different types of service workers, in this case we are going to choose Cache-first Network, where we can pre-cache content. The content you add to the cache-array will be added immediately to the cache and service from the cache whenever a page requests it. At the same time it will update the cache with the version you have on the server.

  • Using PWA builder, go to Service Worker menu

  • Choose cache-first network

  • Add the code generated to your landing page in a <script> tag

Step 4: Install experience and other features

Besides what we have already done, there are different features that you can add to your app including the behavior of an installed app. In order to add this feature (and explore others) in PWA builder go to In this case we already followed the criteria with our manifest file to make Pigment installable.

Step 5: Test your app

Now, you just created a Progressive Web App!

Open your browser and select the install button.

Your PWA has a full app behavior now!!

You can follow these steps with any web app and convert it to a PWA.

You're done!

Congratulations! You have successfully achieved the goal of this Code Lab activity. Now, you can develop a color conversion web app by yourself!

If you would like to learn more about it, take a look into the following links: