What is a key feature that must be supported in themes for Shopify's theme store?

A key feature that must be supported in themes for Shopify's theme store is a responsive layout across devices. This is essential because a significant number of consumers shop using various devices, including desktops, tablets, and smartphones. A responsive design ensures that the website layout adapts seamlessly to different screen sizes, providing a consistent and user-friendly experience no matter how customers access the store.

Having a responsive layout not only improves usability but also affects search engine optimization (SEO) since search engines favor mobile-friendly websites, enhancing visibility to potential customers. As such, themes in Shopify’s theme store are required to meet this standard to ensure that merchants can effectively reach their audience regardless of the device they are using. The other features, while important for enhancing user experience and functionality, are not strictly required for theme store approval.