How can I create rounded header corners in the Dawn theme?

[Jun_Kuan]

I want to make my left and right bottom corners round, I couldn't do it because the section still has background even when adding css to the sticky-header component. I'm lost and I cant find any answers elsewhere so I hope someone could help me.

Here's a sample screenshot: 

In this screenshot I have a 

Here's a share link to my development store: https://tw-dawn.myshopify.com/?preview_theme_id=132785438872
password is: tw

[websensepro]

hi, @Jun_Kuan 

Go to Online Store
2) Edit Code
3) Find base.css file

4) Add the following code in the bottom of the file

header.header.header--middle-left.header--mobile-center.header--has-menu {
    border-radius: 20px;
    border: 1px solid black !important;
}

[Jun_Kuan]

unfortunately, that doesnt work. heres what it looks like with your code:

as you can see, after the rounded corners, theres still a white background.

By the way, thanks for taking your time to reply! I'm a huge fan of your youtube channel!