Page History

...

1. Copy the default theme

1. Locate the ../themes directory in your PrestaShop install, and create a copy of the default ../themes/prestashop/ directory.
2. Rename the duplicate.

...

• In the customized theme folder (e.g., ../themes/MyStoreTheme/), locate the /css folder.
• Open the global.css file and change it according to your needs. This is where you are only limited by your creativity – and your knowledge of CSS.
  Note: the maintenance.css file, located in the same folder, controls the layout of the Maintenance Mode page.
• New or modified images must be placed in the new theme's /img folder (e.g., ../themes/MyStoreTheme/img).

...

Once your customized theme is ready, you must place a file representing the theme, called preview.jpg, in the theme's root folder (e.g., ../themes/MyStoreTheme). This file must be a 100 × 100 pixels .jpg file.

...