Spirituality

1. Copy the default theme
And rename your theme name.

2. Change your theme css

1. In the new theme folder (e.g., ../themes/MyStoreTheme/), locate the /css folder.
2. Open the file global.css and modify it according to your needs.
   Note: the file maintenance.css located in the same folder controls the layout of the Maintenance Mode page.
3. New or modified images must be placed in the new theme’s /img folder (e.g., ../themes/MyStoreTheme/img).

Tips from the PrestaShop development team

• Where possible, use CSS instead of HTML (e.g., for tables)
• Validate your XHTML code on w3c.org
• Reduce images and pictures size by using compression
• Test your theme on several Web browsers
• Keep filenames lowercase
• Homepage text and logo are modifiable directly via the Back Office. Go to Back Office >> Modules >> Home text editor and click Configure.
• Change the positioning of modules on a page or pages by transplanting them via the Back Office:
  1. Go to Back Office >> Modules >> Positions
  2. Click Transplant a module.
  3. In the drop-down list, select the module you want to move.
  4. In the second drop-down list, select where you want to transplant the module.
  5. Type the name of those files you do not want the module to appear (optional).
  6. Click Save.

Prestashop Theme Screenshot changes:

Theme’s root folder (e.g., ../themes/MyStoreTheme) preview.jpg. This file must be a 100 x 100 pixels only.

Prestashop Theme Changes :

1. Go to Back Office >> Preferences >> Appearance >> Themes section
2. Select your theme and click save button.

More reference : http://www.prestashop.com/wiki/Themes/

🙂