I want to override xml file of 3rd party extension in my custom theme in magento 2.1.13 . Till now i did following steps:-
1) path of the xml which i want to override is app/code/Namespace/ModuleName/view/frontend/layout/layoutfile.xml
2) i had changed layout file and uploaded at app/design/frontend/packageName/themename/Namespace_ModuleName/layout/layoutfile.xml
after step 2. i had deleted pub/static/*
and deployed static content again using php bin/magento setup:static-content:deploy
. Then i cleared and flushed cache. still my css has not been changed. please help me