Hi,
You can edit the CSS files of HikaShop via the CSS area of the Display tab of the configuration:
www.hikashop.com/en/support/documentatio...shop-config.html#css
The styling CSS which is added dynamically by HikaShop on the pages comes from the options that you set in the hikashop options of your modules and menus. For example, the background color, or the text centering, etc.
You should not remove it but instead change the corresponding options to have what you want.
In any case, you can override that CSS with the !important CSS trick:
www.electrictoolbox.com/using-important-css/