Magento fall-back on theme -

i installed theme on magento instance, i'd further customize. imagine similar magento's fallback hierarchy theme can fall-back on default packages, should able structure directories in such way can make changes particular parts of theme maintaining similar structure , relying on fall-back.

so here's question: how can develop child-theme of theme, fall-back setup way? performed structuring directories way, or performed other way?

thanks!

if using magento ee 1.14 or ce 1.9 can utilize method described here make child-theme: http://www.magentocommerce.com/knowledge-base/entry/ee114-ce19-rwd-dev-guide http://alanstorm.com/magento_parent_child_themes

important: it's important have theme.xml in app/design/frontend/custompackage/customtheme/etc directory contents shown. failure configure theme.xml correctly prevents magento loading theme.

you must create theme structure noted , place theme.xml file within it, containing following code:

magento ce:

<?xml version="1.0"?> <theme>   <parent>custom_package/custom_parent</parent> </theme> 

magento ee:

<?xml version="1.0"?> <theme>   <parent>custom_package/custom_parent</parent> </theme> 

for versions ee v1.8+ or ce v1.4+, should reference here: http://www.magentocommerce.com/knowledge-base/entry/magentos-theme-hierarchy

heirarchy follows:

1. app/design/frontend/custom_package/custom_theme/ && skin/frontend/custom_package/custom_theme

if not found, then

2. app/design/frontend/custom_package/default && skin/frontend/custom_package/default

if not found, then

3. app/design/frontend/base/default && skin/frontend/base/default

if not found, then

4. throw error

based on place default theme @ custom_package/default , child-theme @ custom_package/custom_theme, files not found @ custom_package/custom_theme fall-back custom_package/default. whatever missing sought @ next level of hierarchy.

set package , theme @ admin > system > configuration > design