Product Size Dropdown

Site URL: http://hamsub.club

Hello,
I am trying to style the SELECT SIZE dropdown menu on my Product Detail pages. I have the text and arrow styled how I want, however I am unable to:

1. Center the arrow vertically in the white box
2. Have SELECT SIZE display properly without getting cut off on mobile. This would probably involve making the box wider, but when I try to do so, the box expands to the left instead of to the right.

Any help would be greatly appreciated.

https://www.hamsub.club/deli/p/test-1
pw: abc123

Thank you