After you have completed the creation of your development store, you can chose any of the following tools to create your own theme, one of which is Shopify theme kit.
Shopify Theme kit:
Shopify theme kit lets you to create a theme development environment using your own development tool, by using theme kit you can do the following things
- use workflow tools like Git to work with a team of theme developers
- upload themes to multiple environments
- watch for local changes and upload automatically to Shopify
- Work on Windows, Linux, and Mac OS.