My css files are not integrated

Hello everyone,
I am testing the application, everything is working properly except the management of css.
When I test my web application locally all pages are displayed correctly unfortunately after conversion, when the launches my application, the css is no longer supported. I specify that I use a cakephp framework.
thank you in advance for your help

Enable Developer Tools in ExeOutput and check the “Network” tab to see what happens to your CSS.

How do I activate it? because I do not see this option.

Thank you ! I understand why the css did not work, I had to put
the link grossly.