If you facing problem of css and design after installation in window please follow the following step
step 1. php bin/magento setup:static-content:deploy
step 2. php bin/magento indexer:reindex
step 3. make sure apache “rewrite_module” is enable and then restart the server
step 4. delete cache folder under var/cache
The above step working for me.I hope this will work for you also.
Let me know if you still facing any problem.
samumaretiya 