In the wizard, the container uses the dynamic class with the if condition takes as sequence wise it will work i have added the condition below
if $currentObject/Sequence = 1
else if $currentObject/Sequence > 1
I Hope this helpful for you.
To use dynamic classes you will need to have a page parameter or another datasource in your page where the steps are nested. If that is the case you can use dynamic classes to change based on a value. Lets say you have an entity Steps with an attribute enumeration status, which is the datasource. If the status is 'active' you want class 'active-step' on your step.
To do that fill in:
if $currentObject/status = 'Active'
After that you can style the classes using SCSS.
Hope that helps