How to edit scroll bar in DAWN

[NOT1]

Currently the code i am using is (for collection list only): 

<style>
.collection-list {
    display: flex !important;
    flex-direction: row !important;
    flex-wrap: nowrap !important;
    overflow-x: scroll !important;
    scrollbar-width: thin !important;
    scrollbar-color: #20374F #f1f1f1 !important;
}
</style>

But I need some changes

1. I dont want it full screen 

I want it  like just with the collection  list image sizes like this image

2. I want it more slim like 5.72 px 
3. Remove the arrows at first and last 

4. Increase top padding from image of the collection list

https://thenewbeast.myshopify.com/
pass- 000
Thanks : )