Come modificare HTML e CSS del tema?

[Moin]

You can create a new theme-component and add that to your theme

@Arkshine

you can create a new component easily through the UI.

1. Go to Admin → Customize
2. Click on Install
3. Then choose Create New. The type should be Component.
   

That’s it! Attach it to your theme; then, you can Edit CSS/HTML

There is also a preview button at the bottom