My first PWA

Hello.
I created my 1st ionic 5 / angular PWA which is online.
1st observation, the css is not at all the same as on the lab.
2nd, after making a modification of the css, it is not directly taken into account in the display, on the WEB I have to do F5. on mobile you can’t do it.
How to rectify this?
Thank you in advance.