1. After successfully installed magento some times CSS & JS won’t load properly in browser.
2. Take source code & check css and js link is redirecting to 404 or not.
3. If it’s redirect to 404 then execute below mysql in DB
insert core_config_data (config_id, scope, scope_id, path, value) values (null, 'default', 0, 'dev/static/sign', 0);