How to modify css property

Due to mandatory of selection of ionic version, I have selected 3 but the issue is coming in v4 and v5.

I want modify the look and feel of UI component as per my requirement but I am unable to modify and not able to add css and class. There are few css properties are given in the doc but that is not sufficient for requirement. I am trying to change height and position of search icon of ion-searchbar. I am not able to do that. Please help.