By default, the platform does not have this option. You can use the following CSS code.

Please follow the steps below:

1. Go to BuddyBoss > Theme Options

2. Under Custom Codes, enable CSS

3. Append the following:

.bp-user .bp-navs ul li.selected a, .bp-user nav#object-nav .selected > a {
    border-bottom-color: green;
    color: green;
}  
.bp-user .bp-navs ul li a:hover, 
.bp-user nav#object-nav a:hover, 
.bp-user .buddypress-wrap .bp-navs li:not(.current) a:hover, 
.bp-user .buddypress-wrap .bp-navs li:not(.selected) a:hover {
    color: green;
}

4. Save changes.

Note: Any modifications are considered as custom work already. Know more about our Support policy here: https://www.buddyboss.com/support-policy/

Screenshot

Timeline is the active link while Profile is the hover color.