With Online Store and Advanced Store plans, you can:
Using preset appearance options
1. Go to Design settings.

In this section, you can edit:
Image sizes and aspect ratios
Product card layout and details
The positioning of the category name
Product page layout (including the sidebar and image gallery)
You can also enable Color Adaptation on this page to automatically match your store with your website's overall design.

Developing a custom CSS theme
1. Go to Design settings.

2. Scroll down to the Themes and in-depth customization section and click on Create theme.

3. Click on Add new CSS theme and paste your CSS code to the code field.

4. Activate your theme and Save your changes.

Note: Only one CSS theme can be active at a time.