When it comes to selecting a theme, the first consideration would be whether it will continue updating. Since WordPress have updates from time to time, it is important to select a theme that will always update.
Therefore, one’s best bet is to select an official theme. Storefront that comes with Woocommerce is a smart choice because Woocommerce will always update it.
In addition, Storefront comes with enough tools for a non-technical to create custom CSS.