@jean-marie
You can use CSS codes for this purpose.
You can find the classes by pressing F12 on the browser and opening Chrome or Firefox Console, it'll help you easily write CSS rules you need to customize.


Don't forget to delete the caches once you make changes.
This website should help you to write CSS rules: https://www.w3schools.com/cssref/default.asp
Important: The images are just examples. You should click on the element where you want to apply the CSS.