How can I style my tracking page such as fill-up and button. Tried last year resolution didn't work.

[KyawZawLin]

Last year’s resolution was to put a section of CSS code. Case link - https://community.shopify.com/topic/2071813

I have put the code at the bottom of the code in base.css but mine still looks like this.

I would appreciate your help here. thank you.