SP 2013 replace specific icon color

I have a custom Css applied to the whole sharePoint sites, but what I want is that the sharePoint Icons was highlighted should come in white.

I have not used themes in SharePoint and have applied custom CSS using custom master page.

I have explored options to create custom themes and then apply in which SP theme engine generates the Sprite images.

But creating theme will be a big ask and hence we want to stick to custom css, but want to replace specific images to white.

Please suggest how this is possible.

Thanks & Regards, Soumyadev | Posting is provided "AS IS" with no warranties, and confers no rights.