Exposed filter form design help needed

Hello,

I need your help with designing the form of a view page which have some exposed filter options for users, both select list and user input. By default, it looks pretty meh, so I need to arrange them properly, make them full block width, make them look better than now. Can you give me any hints where to dig? How can I put both input fields into one row and give them some placeholders? The theme is based on bootstrap. I tried with form ID to style, but it doesn’t give me full control, and my css skill is not very good.

Screenshot: https://image.ibb.co/kNkXCG/Untitled.jpg

Thank you,

Dan.

Drupal version: 


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