HubSpot has finally introduced their latest feature: Child themes

By creating a child theme, you'll be able to:

• Customize a theme's source codes without missing out on future theme updates
• Set up a separate child theme (and branding) for different domains. Each domain now can have its own logo, menu, colors, header, footer, and everything else. 

Here are the steps to create a child theme:

1. Open Design Tools (previously known as Design Manager)
2. Locate the theme you're about to clone. 
   In this example, we're going. to use the Hatch theme.
3. Right-click and click Create child theme
   
4. Follow the next steps