Hi,
It uses the default bootstrap rules.
The "PayPal" button is in the view "checkout | payment" and it is displayed using this line:
<label class="btn btn-radio" for="radio_<?php echo $method->payment_type.'_'.$method->payment_id;?>"><?php echo $method->payment_name;?></label>
You can create a special CSS rule by using his parent id from:
<div id="hikashop_payment_methods" class="hikashop_payment_methods">
About the shipping, it's the same thing but in the view "checkout | shipping".
But the parent div container would have a different id, for the shipping.
About the status (your last image), it's in the view "checkout | status". It uses a span with the classes "label" and "label-info".
<span class="label label-info">'.$this->payment_data->payment_name.'</span>
You can edit the view in order to use another class name or you can create a specific CSS rule using his parent (with id: hikashop_checkout_status).
Regards,