example:
Go to ACP -> Customization -> Theme -> click button </> to edit html & CSS
Go to CSS tab and find Custom.css and add the following
Code:
#elSearchNavContainer{
background:rgba(0,0,0,0.5);
-webkit-border-top-left-radius: 15px;
-webkit-border-top-right-radius: 15px;
-moz-border-radius-topleft: 15px;
-moz-border-radius-topright: 15px;
border-top-left-radius: 15px;
border-top-right-radius: 15px;
}
#ipsLayout_header nav a.ipsNavActive {
-webkit-border-top-left-radius: 15px;
-webkit-border-top-right-radius: 15px;
-moz-border-radius-topleft: 15px;
-moz-border-radius-topright: 15px;
border-top-left-radius: 15px;
border-top-right-radius: 15px;
}
Save & it should now look like the above picture.