Where are error messages encoded?

Hi,

If you have error messages with "alert-error", it indicates that you've activated the "use bootstrap design" setting of the HikaShop configuration so that HikaShop output HTML with bootstrap 2 classes, which are what the default Joomla template supports.
If you turn off that setting, HikaShop will use its own classes with its own CSS to display the messages and thus it will display correctly regardless of what your template is using.

If you want to keep the "use bootstrap design" setting activated but want to modify the class used, then you'll have to edit the function hikashop_display in the file administrator/components/com_hikashop/helpers/helper.php
However, I don't recommend that since you'll loose the change each time you update your HikaShop.

Hi,

As I said, by default that setting is turned off and HikaShop uses it's own classes. That setting is only for people still using a template with boostrap 2 so that they can keep the interface looking like before. That's why that setting is in the "legacy" section of the configuration.
If you read the documentation for that option we say in bold:

Since HikaShop 3.0.0, this option is not useful anymore as views are automatically responsive regardless of Bootstrap. However, if you're updating HikaShop from an older version, this option might still be useful for old view overrides you might have.