Go to the Appearance tab in the Settings page

Pick a name for your theme

Click on Set theme to make this your current active theme.

Click on the Edit button to start working on it.

Two windows will open. One is the theme editor, where you will write the CSS for your custom theme. The other one is the Dev Tools for the main window, where you will be able to debug and see all the current HTML and CSS to help you write your theme.

And now you can make your Hydra Launcher looks however you want:

In the next article we will cover how you can publish your theme in the Hydra Themes Store