Woocommerce Features request

I need a way to customize Shop Sorting drop-down and single page product Quantity drop-downs

I asked my theme support, and they said it’s not possible unless we create a separate JS library for that tiny thing, and it affects page load performance, so we rather don’t do it, and they suggested asking here as a Woocommerce Features request.

So, here I’m asking for a way to drop-downs inherit theme styles without affecting the page load speed.

On one of my client’s websites, he demanded using only black and white colours, and this drop has a blue colour, it becomes a huge headache, at least make them inherit from theme styles, border-radius, hover colours and ect, please.

Video for better understanding: https://www.screencast.com/t/sGh8cuGulR
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The page I need help with: [log in to see the link]