Hello
This is untested but you can try applying this styling to the 
hr tab by adding the following to the Custom CSS field of your template settings...
hr {
	position: relative;
}
hr::before,
hr::after {
    position: absolute;
    bottom: 0;
    left: 0;
    height: 4px;
    content: '';
    opacity: .8;
}
hr::before {
    background-color: rgba(0,0,0,0.25);
    right: 0;
}
hr::after {
    background-color: var(--primary);
    right: calc(100% - 70px);
}
Ciaran